Installed the H-Fit kit yesterday. Very straightforward, once you get those @#$$@#%^ buttons out that hold the front of the console in. Honda should be shot for using that junk! Aside from that it went smoothly. I was done in less than an hour.
The H-Fit parts are nicely made and fit very well. The instructions were complete and clear, once I rearranged the pages in the correct order.
If there is any advice I'd offer to prospective installers, it is to definitely tap the adapter down onto the end of the lever ball. Tapping it with a plastic hammer caused the adapter to go on about 1/4" further and allowed the setscrews to bite into the shaft proper -- where they're designed to bite. Doo eet.
Shifting performance is definitely better. Throws are shorter and crisper, with a little increase in effort but nothing excessive; I swear the only reason I notice is because the shifting effort was so very light to begin with. Precision feels about the same. Rubbery feel in the lever is gone due to the hard mounts. I noticed no increase in NVH whatsoever, which makes sense given that the whole deal is cables and plastic to begin with.
I find plenty to like about the H-Fit kit, and nothing to dislike. It's well designed, well made, and works as advertised. I'm satisfied.
I'd still like shorter shifts, but that's probably because I'm comparing the Fit to an STi with a heavily modified shift mechanism. I may combine the H-Fit kit with a T1R lever, if I can find somebody who sells them...