Hmmmm every body has their favorites..
If you want bottom coil, I am very happy vaping on my Fogger V2 at this precise moment, but some people have absolutely tore it to bits as being the biggest piece of crap ever made.. I must admit it was a bastard to sus out setting it up, took me about 10 builds to get it right, since then it has worked a treat.. but I did nearly launch it up the garden (several times).. great flavour and clouds of vape once it behaves..
If you want a Genesis style RBA, the Kraken seems to get a thumbs up from most people who have had success with Genesis atty's..
The Kayfun 3.1 is a few quid more but they got good votes when I asked the same question a couple of moths back..