I have three different feeders on my desk and they each have a different atty. - My VVPV (I realize the question is bottom feeder specific and the vvpv is a top feeder) has an hh.357 on it. My REO Mini has a 1.8 ohm 306. And, my REO VVW has a 2.5 ohm i06.
I chose a 1.8 ohm 306 for my Mini as a good balance of performance vs battery life. - The mini is an unregulated 14500 mod, so battery life has to be considered. Standard resistance attys on 3.7v unregulated mods just doesn't quite cut it for me - and 2.0 ohm is still not quite warm enough... but 1.5 ohm drains the battery too fast. So, 1.8 ohm it is and that's good enough for a single battery swap per work day. - there's something really satisfying about the nice warm vapor from a good 306.
The hh.357 is my favorite atty but I tend to flood it blind squonking my REOs - the i06 is a close second for flavor and vapor production and much more forgiving to being a little over fed occasionally. So, I settled in to 2.5 ohm i06's for my REO VVW. They give me pretty good flexibility for voltage adjustments and they perform very well. - I will say that I've experienced some QC issues with the i06 since I've been using them. Some of them have been pretty far off the advertized ohms (I won't buy them for a non-VV device because of that) and a few of them have come with such a tight draw that they were unusable without modification (not a really big deal - just takes about a minute to hog out the air holes with a drill bit).
the hh.357... Well. If I spent more time at my desk or on my sofa, I'd probably be happy with the hh.357 on my bottom feeders. As I mentioned leading the previous paragraph, I tend to over feed the hh.357. Using the visual method of squonking, I can feed an hh.357 perfectly every time, but when I'm driving or doing anything else that requires my attention, I blind squonk and have just never gotten a good feel for blind squonking the hh. It can and will spit lava-hot e-
juice in to your mouth if it's over fed. -- The hh.357 is excellent under any and all other circumstances, though, such as dripping or on the top feeder I mentioned - or if you use the visual method of squonking.
I've used quite a few other attys along the way. There are probably a few that should deserve some honorable mention, but the three I mentioned above are what I'm most likely to use on my feeders.