I think they actually look cool!
And I'm glad, but my opinion of this new version has changed in the past few weeks before seeing this, anyway.
As a boy I LOVED TMNT. It's been revamped like 5 times since then, and it's not like the TMNT I (and many of us) grew up on in the early 90s was so similar to the original comics that this Michael Bay version is committing some blasphemy that hasn't already been committed by the past dozen iterations. It's not like the comics themselves haven't changed continuity with it's jumping between publishers. It's just another version of the characters, and this version looks cool.
But looking cool is one thing, now if it will be any good is something we'll have to see. The 1st Transformers movie was decent, whereas the sequels drug the overall franchise down, so TMNT might be good as well. And from what I recall, the 1st TMNT movie with it's kind of serious tone was a decent movie with less than great sequels, as well...