I don't recognize all the returning designers, so I can't speak much for their skills or whether I think they are strong competition or not, but a few of my past favs are back, thankfully.
He was totally robbed his season, I'm sorry but he was. Gretchen's designs were nice but (IMHO) they were much more commercial than Mondo's (plus she didn't seem to be nearly as down-to-earth and passionate about winning).
However, Mondo may want to look out for Austin Scarlett - besides being delightfully flamboyant the boy is talented. And I believe he has many years of bridal design experience under his belt (I saw him on Say Yes to the Dress once, I'm pretty sure!). As for the others I recognize, I can only remember small bits about them - Anthony made funny comments, had a delightful Southern accent and made (frankly) some pretty beauty-queen-tastic (aka. tacky) dresses. Kenley had a cool, retro pin-up girl style but as I recall she was vaguely annoying (same with Michael, who I remember as being very whiny). Mila was pretty bitchy and...honestly that's all I remember about her. I recognize Sweet P but don't actually recall what I thought of her designs (forgettable is not good, I'm sorry to tell ya toots).
Time to break out the scissors. Because in fashion, as you know, you can be cut at any time.
On a not-completely-unrelated note - I have a confession to make: one of the things that amuses me the most about Project Runway is Swatch the Dog - he is the resident pooch at Mood Fabrics where the designers do all their shopping. Get it? Swatch? Cutest. Dog. Name. Ever. Oh, and guess what else? He has a blog! Well the store does, but lets not nit-pick...check out The Daily Swatch here (it's a great pick-me-up on a sour day).