I use them on a bottom fed mod and it's a bit more involved than a 306 or 510, but if you are feeding it properly you will be rewarded with a really nice vape. I usually feed and suck on the atomizer (while not firing) until I get a nice gurgle. Any less and I am getting a very dry burning hit, any more and I may leak. Once I got the hang of it I haven't had an issue either way. I actually find bottom feeding them more forgiving than dripping. Dripping, I had a harder time with dry hits, but the key I learned is patience.
What I like so much about these 801s is the taste, though. It really can't be matched by anything out there.
I agree regarding the heat being similar but the TH better than an similar ohm 306 or 510. Weird when you think about it, but it really does feel that way. You're not getting scorchy hits, but you are getting that nice extra kick in TH.
Edit: Forgot to mention, regarding the stiffer draw - if you are using a 510-801 adaptor, try loosening it up a tad to lighten the draw.