Its always has been, and always will be, a department store bike is junk. But some people don't know any better.
There are some good bikes at REI - I believe they have their own design dept.
Mail order bikes can be ok, as many have an actual store front shop, so they know bikes.
But do yourself a favor, and go to your own local neighborhood bicycle store and get a bike with a little more (probably a lot more) quality.
You will like bikes more... And you will thank me later.