I've vaped a lot of different ecigs, all sorts of mods, even made mods and cartomizers, atomizers, dual-coil low res cartomizers, tank mods, etc, etc, etc. But now I vape the SmokelessImage Volt. If that Smoov 65mm battery lasts 2 hours of heavy vaping, then it probably is very similar to the Volt. The Volt doesn't make that slurpy airy sound that the Smoov does with its teeny-tiny air hole down the center of the battery. The Volt 78mm battery lasts 4 hours of heavy vaping. The cartomizers last about 5 hours before they need topping off with a few drops of e-liquid.
For me, I just like automatic batteries so much better than having to press a button and all the flavor and vapor without having all the hassles of the Ego or other atomizer/cartomizer and etc ecigs. The Ego was my first ecig and I did not like having to fill up cartridges and stick them on top of atomizers and then fiddle with them for several minutes to get it to vape right and then 20 minutes later, have to do it all over again.
One thing you're going to get on these forums is a lot of folks who are now into what I call the hobbiest category. They want the biggest, shiniest, most milliamphours (mAh), highest priced models available. The last time they tried a small ecig like the Smoov or Volt, if it was prior to 2011, it was a terrible experience, batteries lasting 20 minutes and prefilled cartomizers tasting like dirty socks. They will browbeat you that the only way to go is bigger, shinier, more expensive, and a whole lot more fiddling with things that use 10-times more e-liquid in the same amount of time than what you have now, and they have no idea that the vaping experience between yours and theirs isn't all that different. Been there, done that.
So if you are looking to get more pv's because you need more batteries but are satisfied with your vaping experience, then you might want to check out the SmokelessImage Volt. If you want more pv's because you are curious about all the toys out there, yeah, maybe an Ego Tank System or an E-power, something along those lines. Those will be 510 threaded connections between the battery and the atomizer, so you will not be able to use your Smoov or other 808 threaded cartomizers on them, unless you get an adaptor (goodprophets sells adaptors for cheap).
As for what mg to get, it's all personal preference. Nothing's going to beat trial and error. If you are still feeling nicotine cravings, go up in mg for now. If you are not having nicotine cravings, then it's pretty much whatever you want. I've heard and read that increasing nicotine for most e-liquids increases that "throat hit" that simulates cigarette smoke better.
Congrats on your success!!!!!
) but i do find that it seems i get much better vapor, etc from the 808 than i do from the eGo. i don't have tons of money to spend but i do at least have some options 
but when it's all said and done if i could only have one it'd be the 808.
