One of the guys here at my work wears 'em ocaisionally. They look like they're made pretty well.
Personally, I think I'll stick with "convertible" REI Sahara pants with zip off pant legs. When I'm in brush, I zip 'em on -- especially now that Lyme Disease ticks have made it out this way. When I'm out of brush, I zip 'em off. They have ankle zips so you don't even have to take your boots off.
I'm not as familiar with MEC, but I think the link below looks similar to what REI has.
REI:
http://www.rei.com/product/746908MEC:
http://www.mec.ca/