Arc'Teryx's Theta LT pants are a case in point. They, too, look fantasticdesigned a bit like a short bib with shoulder straps, articulated seat and knees, Gore-Tex XCR fabric, various reinforcement points (www.arcteryx.com). But, yes, they're also $350! Of course that will make anyone pause and think for a minute. In their defense, I'll say that the Thetas work as well as any pants out there, and unless you're glissading down granite slabs, will last for many years.
On the other hand, we have the Flight Pants you mention from Canada's Mountain Equipment Co-op (www.mec.ca). On key points, they're similar to the Thetas: Gore XCR fabric, Schoeller stretch waistband, a short-bib style with shoulder straps. And the price is very attractive at $275 Canadian, which despite the stronger Canadian dollar of late still translates to around $200. That's a good price.
My recommendation, then: Go for the MEC pants. I own several of that company's products, and think the construction is generally excellent. Maybe not quite the detailing of the Thetas, but still more than acceptable. Good warranty, too, so if they blow out for some reason you can get them repaired.