The name is not Amber, but Amber.js, which for me is clearly a js framework and as a whole a good, unique name. I do not think there will be a lot of confusion.

Also I do think that moving away from Sproutcore is a good choice, because when I talked with fellow rubyists about Sproutcore, I always ment Sproutcore 2.0, but this always caused confusion because people always had 1.0 in mind (it is huge, too much, ... which it is not).