He's pretty damn good. I thought RG3 and Wilson were better last year, but I think RG3 is fragile. I can already see 5-10 years down the road and they will be talking about the #1 pick Luck and this guy the Seahawks stole in the 3rd round. RG3 will be that "other guy" who flashed potential. Tannehill will still be alright and maybe even pretty good, and Weeden will be retired or some random back up. Osweiler might still be around, but I think not.
As far as Luck goes. He's way more athletic then he looked at Stanford. Smart, great arm, durable. Yeah he'll be good for a long time.