My experience is quite consistent with mischiefgrrl's. I'm new to e-cigs... just a few days into it and I've cut down significantly on the analogs already. I was smoking an average of about a 1 & 1.2 packs a day, though 2+ packs was not unusual. For my first few days using e-cigs I've cut analog use to no more than 1/2 pack a day, with most days being more like 5 or 6 cigarettes. I can definitely feel myself headed for zero analog use soon. It is nice to feel that I can allow myself to wean off of them as opposed to something like the patch that is basically cold turkey with a nicotine supply. E-cigs do not feel like cold turkey.
I ordered the Blu kit and then found this forum. My initial reaction to all the negative reviews was to cancel the Blu, but after further contemplation I realized that the anti-Blu sentiment was coming from folks who got irritated waiting for so long when Blu was out-of-stock, had some sort of agenda. Most of the reviews I found of people actually using the Blu were favorable. Nevertheless, I was concerned about the wait so I ordered a Joye 510 as well. The 510 arrived within 3-days and I started with it. It took a week for the Blu to arrive (ordered 9/8, arrived 9/15).
I am extremely happy I got both of these. They are different animals, each with there own advantages and each with there own purpose within my lifestyle. Here is my head-to head comparison. Some of differences are simply manual versus automatic and might be applied equally well to other models.
Activation:
The Blu is automatic whereas the 510 is manual. That is, you just suck on the Blu and it makes vapor while you must press and hold a button on the 510's battery to activate it. The Blu can be activated by outside input such as wind. I'll be using the 510 when driving my convertible with top down. I've seen some comments about the Blu self-activating with loud music. I'm not a club goer, so likely this won't be a factor for me. I did experience an unintentional activation issue with 510, though. I stuck one in the pocket of my jeans and the battery button was accidentally held down while I was sitting. The thing got real hot in my pocket. It smelled and tasted like burnt plastic. I ditched that cartridge and after letting it rest overnight it only took a few drags on a new one to eliminate the foul taste, so no real harm done.
Form factor:
The Blu is about the size of a regular filter cigarette. The 510 is a bit bigger than a 100, and a little fatter. Frankly, I would not be happy with the 510 if it were any smaller. Since you have to find and hold down the button on that one, you don't really hold it like a regular cigarette and the extra size helps with finding a comfortable grasp. On the other hand, the small size of the Blu is nice for an automatic. While heavier than a cigarette, it's still light enough that you can hold it between your lips while taking a drag... sort of the standard smoking routine for many of us... stick it up to you mouth and let go while you draw, then scissor it between fingers again to remove once you're done. So, the Blu is a more natural "smoking experience". The 510 is likewise enjoyable, though with a revised technique required.
Vapor production:
Both of these models are capable of producing more vapor than I can handle inhaling at once. However, the 510 is more forgiving about technique. I can get it to make satisfying amounts of vapor with long slow drags as well as short sharp ones. I also got a USB pas-through for the 510, but it does require a little more focus than a fresh battery to get consistently good mouthfuls of vapor. The Blu also requires a little more practice and patience, preferring lighter suction, though with a full cartridge it doesn't take long to produce a full mouthful of vapor.
Throat hit:
I didn't completely understand what everyone on the forum was talking about until I tried an e-cig for myself. For anyone else confused, it's much akin to what you'd call harshness in a real cigarette. If it's too silky smooth I won't emulate smoking very well, and if it's too harsh it's hard to handle without coughing. For me, it's not just the initial hit when inhaling, but maybe to a bigger degree the feeling in throat and lungs after inhaling. I have to believe that it's the liquid that is most responsible for throat hit and/or harshness, but I'm sure are differences in what each type of e-cig does with it. Both the 510 and the Blu have done a great job with all the cartridges and liquids I've tried, though admittedly I have not tried a lot of different ones.
Flavor:
Hmmm... OK... I've only tried tobacco based flavors so far and all have been good for me. I got 3 flavors with the 510, Joye "Marlboro" cartridges and liquid, Joye Tobacco liquid and Ecopure Rich liquid. All are nice. All are different. The "Marlboro" is the most neutral, making for a relatively acceptable substitute for regular cigarettes. The Joye Tobacco flavor reminds me a little of Mac Baren Club Blend pipe tobacco... a little musty, but very enjoyable. The Ecopure Rich is on the sweet side, but with tobacco undertones that make for a very enjoyable "smoke". The Blu's standard Classic Tobacco cartridges are probably the closest I've yet tried to a real cigarette in flavor. Unfortunately, they do not offer liquids so unless you're willing to pay a higher price to use cartridges exclusively you'll need to find a liquid you like (more on that under "capacity"). The Blue came with several other flavors that I have not tried yet. I'm first and foremost interested in replacing real cigarettes and for me that means using tobacco flavors.
Cartridge capacity:
The 520 cartridge appears to hold about 3 x what the Blu cartridge does, though how much of that actually gets wicked up is hard to say. Since vapor production is at its peak with a full cartridge I find myself topping off the carts with liquid long before I've ever reached the limits of what the 510 carts can provide. The Blu company obviously approaches things a bit differently, hoping that you'll just keep buying carts from them when you run out. That's all well and good, but it's so much cheaper to refill them. With the Blu the capsule is buried deep in the cartridge and you need to push it up to refill. Use an open paper-clip to do this and then push it back down in there. Do not push it all the way out, just up to the top where you can see what you're doing. The Blu also has that foil cover on new carts. When using a new one, I press the cart on then remove it and flick the foul cap off the atomizer before using. As has been pointed out elsewhere, it's nice to have extra atty's to cap your carts with if you're going to refill Blu carts. The PCC will hold carts with atty's.
Battery life:
I read that battery life is a big factor for a lot of folks. I guess it depends on you're expectations. I have not been disappointed with either the 510 or Blu. I expect to run batteries down. With both devices I have 3 batteries and PCC's (portable charging cases). I also have enough atomizers to build three complete units in each brand. I highly recommend this. Unless I'm out and about with only a PCC to rely on for back-up, I can keep 6 complete units at the ready, rather than treating as a single ecig with fresh batteries going in and out.
PCC's:
What a great idea these things are! Frankly, it was Blu's charging case that initially sold me on that brand. I also have one for the 510. If I'm going out for the day I'll carry the PCC's with extra batteries and cartridges, as well a couple of e-cigs ready to go. As has been noted many times, the Blu pack has a place for a complete assembled e-cig while the PCC for the 510 does not. The Blu pack is about the size and shape of a pack of regular cigarettes. The 510 PCC is narrower and longer... maybe closer to a pack of Virginia Slims or Capri. I've seen comments about the lack of space for an assembled 510, but most smokers are used to carrying a lighter separate from their pack of cigarettes, so bringing a separate 510 along with the PCC isn't that much of a stretch (my experience with accidental activation notwithstanding).
Conclusion:
I am extremely pleased with both the Blu and the Joye 510, but for different reasons. I think having both is an ideal situation for me and I would recommend other newbies who are serious about replacing cigarettes with an e-cig to consider getting some sort of automatic like the Blu along with a 510
and make sure you purchase extra batteries and attys so that you never have to feel the threat of downtime forcing you to go back to analog. If youre budget dictates that you must choose one or the other then go with the one that best suits your outlook. Id consider the 510 the more reliable one with easy to refill carts that last longer than the Blu. 510 parts are easy to come by on the open market. If on the other hand you want the e-cig experience that mimics analogs most closely, then go with the Blu or some other small automatic.