I never use my lockout. Lockout does nothing on a cheap fork and good forks don't really do much bobbing. Honestly, both of them have relatively entry level forks that, if and when you get serious about riding, you'll probably want to replace. The Revel is built around an 80mm fork while the 4300 is built around a 100mm, but either should be able to take a 100mm if you decide to upgrade. Disc brakes are nice, and even if the current ones aren't top notch, it ensures that you're disc ready if you decide to move to nicer mechs or hydros. The rest of the specs look comparable.
That said, either one will work great as a campus commuter and for the odd trail ride. Both of them are nice frames. Have you taken them on a test ride? There's a good chance that the differences in geometry will make for slightly different rides, so it would be useful to figure out which one feels better. Buy the one that makes you happy.
More & more companies are sticking tighter to their warranties instead of bending the rules with this bad economy. It's no surprise Trek is doing the same thing. If it was me I'd expect the bike company to take the bike, sand the paint down, inspect it, then touch it back up to make sure it's not some frame stress fracture. I think I am going to go with the Trek on this one. I like both but am just pulled towards Trek with the upgrades it has over Giant on this particular model.
Giant is using pretty shoddy disc brakes on the revel 1 to begin with. I can always upgrade my Trek down the line to disc brakes.
I really appreciate your input though. It has put me on a reading expedition through Trek & Giant with reviews, problems, etc. and has gave me more peace of mind. And for that, I thank you.
If you think you may upgrade to discs, check to make sure the frame and hubs are disc compatible. Otherwise you're looking at some expensive upgrades, and may be better off buying a new bike at that point. It sounds like you liked the way the Trek rode though. Good deal. Enjoy it.