I own this one:
https://www.fasttech.com/p/1427800
It's a favorite, with a few caveats. The fact that it's aluminum+brass means it has very good conductivity, and is also surprisingly light compared to other mods I own. The fact that the locking ring is NOT reverse-threaded is a big plus for me.
The fact that the head is aluminum and 510-threaded means you really want to add a 510->ego adapter to protect the threads. I screwed it down as tightly as I dared. Just be careful with the threads! (I think you can get a replacement top cap from FT if you strip the original...) Also, the vent-holes are pretty small, so make SURE you're using a good battery!
As others have said, the battery (and the head) are more critical, but I like this mod.