I think they're both amongst the best tactiles as close to the MX browns you're used to that you're going to find in an OEM board. I find the Gaterons to be a bit smoother out of the gate, but the tactile event is more rounded like traditional MX tactiles, whereas the box brown tactile event is higher and sharper.
Besides having to worry about box browns going clicky, there's no wrong choice there if you want a tactile that comes in an OEM board and is somewhat similar to MX. It comes down to preference.
Personally, I can't even feel the tactile event on MX browns unless I press them very slowly, otherwise it just feels like there's sand in the switch, so I don't know what your perception of that tactile event may be, and if you want as close as possible to that (Gateron, except smooth and you can actually feel a bump) or something a little sharper and a bit more tactile (box brown).