Good question- I'd like to know the answer(s), too.
The couple pairs of pants & sweater I bought DD at the Carter's store seemed to be the same quality as what you'd find in BRU/ Kohls/ Macy's, etc. However, I guess it wasn't an 'outlet,' just a separate store.
I thought that Gymbo outlet clothes are just clothes from previous seasons, but maybe not.
Hanna: the quality seems exactly the same from stores & outlet. I got a pair of pink & white striped ljs for DD as a gift, and when I went to the outlet months later, I got her another pair (bigger size for later), and they're the same (just a bit cheaper). The stuff at the Hanna outlet was just more random- previous season stuff, etc. To tell the truth, even the stuff at the outlet costs more than I want to spend, but I did buckle and buy about 3 sweaters & a pair of ljs (DH was along and fine with it). There's nothing different on the label to designate that they're for the outlets, I think they just send extras there?