I have used my Project 1 extensively and a helluva lot harder than most for over two years now, I have absolutely no complaints about comfort, ergonomics, and haven't had any problems whatsoever about transference of shock through the handle.
As I have stated, it was not the hollow handle that drew me to this knife. In fact, I've got a machinist maiking me a tempered steel endcap right now that will be permanently fixed.
The main reason I like this piece is because I use my knife for everything from killing and cleaning game, to building a camp and food preparation. There are a plethora of little harmful bacteria that can take up residence between blade and gaurd/handle scales on a multi-piece knife. I for one don't like that idea. Especialy with all these bloodborn pathogens going around these days.
As for temperature and the metal handle, after extensive testing and evaluation, I have found that this is only a problem in the coldest environments. Not an artic knife, but no problem anywhere else. Remember, Reeve designed this knife while he was a soldier stationed in a desert region.
Uh, guys, you don't put your whole kit in your knife, that one's a no brainer. The idea isn't that you replace a backpack with a hollow handled knife, the idea is if you have your knife, you've got some other stuff too.
I have a pouch for my sheath too, now if I have my knife, I have all the basics I need, even if I lose my pack.
Condoms suck, no pun intended, for water carrying. The slightest little prick(hehehe) and the thing will burst, meaning you lose your water. The best place to cary water is in your stomach, where it does you some good, or in a canteen if you have some extra. Condoms are for smuggling drugs and making love.
The reason you don't want that butane lighter in the hollow handle is because it's airtight. The butane lighter leaks, and then you're talking apocolyptic fireball. I know, I tried.
Matches are safer for long term storage in the handle, keep the blowtorch in your pocket.
I understand the aversion to hollow handled knives in the survival/adventure industry, but practical experiment has proven many of the above point to be false or of little worth.
Not that I'm arguing for hollow handled survival knives, like I said I'd still have the Reeve even if it didn't have this feature, and am sealing up the cavity on mine to fix the only real problem with the knife; if you do a whole lot of extensive chopping, the endcap will try to unscrew. I can't chop long enough without resting to make this happen, and I'm in pretty good shape, but it would be nice to not have to retighten it when I take a break. A little LokTite will fix this too. If you've got the lanyard around you wrist, it doesn't matter anyway, as even if the endcap did unscrew, it'd still be hanging from your wrist.