Everyone has a personal preference, and it depends what you want to use it for. If you want to do lots of super fine detail, then a dedicated gravity detail brush might be better, if you plan to use lots of paint over larger area, you might want a siphon, or you might want a mixture of both but find a detail brush wont give the coverage you want. Then again some people just feel more comfortable or better balanced with one or the other.
It's more a personal preference than a matter of one is "better" than the other. Both work but there is something to be said for the fact that one is more suited for some situations than the other.
Bottom is generaly used for larger nozzle sizes that will use up more paint. Having a large cup on top will make the gun hard to use (ballance).
Top feed (gravity) is generaly used with smaller nozzles that requier less paint (bottom feed with the bottle, length of the tube to the bottom etc will by default requier a lot more paint than a top feed)
I just picked up two Bottom Feed Talons should be here tomorrow every brush I have is Gravity so far. I do have one Paasche H for stippling
I hate cleaning it though kinda awkward I like it though because of the line of sight from the nozzle to the paper I'm painting the color cup is out of the way.
Just tried these out they are really nice I used to own a Paasche VL in the 90s it always clogged on me.
I like the line of sight on the Paasche Talon TS bottom or side feet with the color cup. I think I might sell some of my Talons now with the color cups on top. The Raptors are pretty good but the TS has a good bead from the paper to the point of the airbrush cap and tip.
I always regret selling extra airbrushes later on though.