Every day, I use bottom feed REO Grands with cotton-wicked, micro-coiled Reomizer 2.0 RDAs, and IBTanked carto tanks with LR cartos, as well as drip bridgeless disposable atomizers on my Super-T Simplicity. I also have a couple of Kanger ProTanks set up with AVE's Boba's Bounty and Cuban Supreme on a Joyetech eVic I hit every now and then.
If I could have only one, it would be a REO Grand. My well-worn raw aluminum Grand is my daily driver. It's the only one I take out of the house. With a 6 ml internal bottle and 18650 battery in such a tiny package hidden away in a back pants pocket, I'm good to go for 15-16 hours. The first thing I do when I get home is top it off with my cigar-flavored DIY and swap in a fresh battery so it's ready to go at a moments notice. It carries a still "safe for work" 0.8Ω micro coil and is second only to my powder coated Grand/RM2 with 0.5Ω coil in terms of vape. I wrapped this coil August 1st and it's still going strong.
Changing flavors in a REO Grand/RM2 can be as simple as swapping the bottle if the flavors are in the same class, i.e. tobacco flavors, fruit flavors, etc. There's only about a minute of vaping both as the new flavor overtakes the old in the cotton wick. Changing flavor classes adds a 60 second change of cotton in the micro coil, or having multiple Reomizers for flavor classes. I have four for my two Grands. Each costs $43, not a lot more than I pay for an IBTanked tank and a five-pack of cartos.
So why do I use carto tanks every day? The vape intensity or flavor don't compare to an RDA. A dark, thick juice, especially a NET, can clog a carto to useless in as little as a day or less, making it a very expensive way to vape compared to an RDA. It mutes the nuances out of the flavors in my expensive juices. The reason is I have a couple of lightly flavored DIY juices, and in particular, a tobacco absolute based DIY juice, that I prefer in a less intense carto.
Filling a carto tank is much easier with a tank tool or drip tip made for filling, such as the
IBTanked refilling drip tip or the
ByLeo Nail. I can do it without one by pushing the connector down in the tank and leveraging it to the side with the drip tip, but it's not fun. OTOH, there's no need for a tool when a carto clogs or burns out, even if the tank is near full. I just put the connector of the new one in the top of the old one, push the new one in past the first o-rings, invert the tank and push the new one all the way in past the other caps o-rings. But here's the rub... you have to carry a spare carto primed with the flavor you're carrying in the tank. Trying to prime a new carto by letting juice migrate from the tank is a slow, unreliable process. My on-the-go solution is a matchbox-sized plastic two-battery pack with an 18490 battery on one side and a complete 19 mm carto tank set up on the other side. These are also useful if you swap flavors on the go. But I always defer to the REO.
So why do I still drip disposable bridgeless atomizers? Aren't they the most expensive way to vape? Isn't the REO like dripping? Yes, they are expensive, and you go through them a lot faster with dark, thick juices such as NETs. Their life is variable. You might get six hours, six days, six weeks, or six months out of one. But IMO, they are worth it. Nothing is quite like them when it comes to nuances of flavor in complex juices. It's just me and the coil and the drops I put on it, and I just prefer to do it on my Simplicity.
Yes, the REO with a bottom-fed RDA is like dripping--in an RDA. To me, that's not the same experience as a disposable atomizer. You can still manually drip into a disposable atty on top of a REO, optionally using a sealed 510 to 510 adapter if you don't want what you're dripping to get down into your juice tube and bottle. And of course, you can bottom feed a compatible disposable atomizer. There are some kludge setups, but a bottom feeder is the only practical safe way to drip while driving.
A delivery device I've yet to explore is the carto-sized, ceramic-based, resistance wire + non-resistance wire rebuildable attys, such as the Sophia. While they're designed to be used with carto tanks, some are bottom-feed compatible, and some can be used as a manual dripper. They aren't cheap, but over the long run, may be less expensive than disposables, while giving a similar experience to a disposable when dripping. I am anxious to try one.
I keep the clearomizer on regulated mod around for the beginner experience. It helps me keep things in perspective, especially with the popular BB lab tobacco many use.
So there you have it--my perspective. Carto tanks are a clear step up from clearomizers, and some are satisfied with them. Most step up from cartos to RBAs, either RDA drippers or RTA tank types. Dripping is the ultimate vaping. The bottom feeding REO gets my vote for the most versatile setup.