Your average REI tent vs. a Wal Mart cheapie will be:
-more compact, easier to fit in a backpack/ on the back of a motorcycle
-better construction/ value/ resale
-the latest design, easy set up (esp in the dark after a few beers).
-better customer service & warranty.
I have owned cheap ass department store tents....then graduated to a Sierra Designs Jupiter (over 150 days in use). My buddy works for MSR/ Cascade Designs and gifted me some state of the art kit....can't be happier with my Hubba (roomy one person 3lbs) and my Hubba 3.
But if I was paying retail, I'd probably go to REI. Their online outlet deals are pretty good too.....especially this time of year.