At $450, they're a better value. As far as the brand, GT seems to be fine. They certainly have a long and storied history -- the current brand name is owned by Dorel Industries which also owns Cannondale, Schwinn, Mongoose, and others. We bought our daughter a GT Laguna Pro from Dick's about this time last year, at the time for $299. It's a basic hard tail mountain bike and has been good. We picked one off the rack which appeared to be assembled okay. I needed to fix some things on it when we got home (certain cable routing, derailleur adjustment, etc.). I think Dick's probably assembles bikes better than a place like Walmart or Target, but attention to detail won't be as good as from a local bike shop.
For what you describe, I think the rigid fork hybrid may be a good option for you, especially if you can fit larger tires on it (like 40-45mm tires perhaps). This would give you a nice balance of ability on the road while still being somewhat capable on off-the-road trails. There's nothing wrong with the suspension fork model either -- I have a Giant Roam which is basically the same concept, and it's one of my most-ridden bikes.
A test ride will probably tell you which one is for you.