I've had the best luck with Outdoor Research Gaiters. I use their Expedition Crocodiles exclusively. I work for the Forest Service and we end up burning slash piles into the winter until snow keeps us from getting into the woods. I've never had any complaints about them. A couple years ago I was on a hunt in Alaska with my dad and he had the Kuiu Yukon Gaiters and they got a sizable tear within the 10 day hunt. My expedition crocodiles didn't have any issues. They're built ruggedly and whatever weight they do have reflects that. Cheers!

I'm not busting brush in all the time in (equally humid) East Tennessee, but over all I've been pleased with the eVent gaiters that Ron Bell at MLD made me.  Other than having to replace the shock cord periodically, they've held up to a lot of trail miles.  Again, I was wanting something mainly to keep out trail debris--they won't be nearly as robust as the OR, etc. but I'd venture they'd be as cool as anything you'll find on the market.

http://mountainlaureldesigns.com/product/superlight-gaiter/

I've been using OR crocodiles for awhile now, and they are a great rugged gaiter. I use the expedition style over bulky mountaineering boots. The downside for me is that they aren't that breathable, and are a bit bulky and heavy to carry all the time. That being said, in the winter they are almost always in my pack regardless of how likely I think i'll be to use them.

Excellent, I wear mine with a pair of FGL boots and usually stay pretty dry (a lot of the trails here in the Smokies are pretty much creek beds six months out of the year.) It definitely pays to have a roll of shock cord in your gear bin, though, if you're putting in a lot of miles over rocky terrain.