It's looks like Sonic and crew have a new look going.
I like Knuckles buffed visual, I think it fits his gameplay more, and also makes him more than a red-colored Sonic.
I have no strong opinion of Sonic new visual. I think it suffers from a case of "less is more" so I'm not an huge fan of the current version, but perhaps the scarf turns red and long if he goes Super Sonic which could make for a nice visual.
Amy is better I guess? She also suffers from being a pallete swapped Sonic so anything which makes her more different from Sonic is a plus.
Tails is unchanged so there is nothing to say here, his design is probably the closest to the origina designl since creation.
I'm sure some fans will cry about this being an abomination and all. While I may like Sonic original design a lot I think the newer versions fits more with the personality they decided to give to him. You can really see the contrast when you play Sonic Generations.