Can't say I agree personally on UI Grid - it's a bit of a mess in some ways, especially in its distribution. It is also a bit of a configuration nightmare.
For high quality JS, I would look to some of the major frameworks out there:
There is a lot one can learn about software design by reading the source code of major libraries, and is far more reliable than any third party library in the ecosystem.
A smaller, more accessible project would be Mithril, very nice, clean code. I haven't looked at the v0.2 code yet, but I can't imagine it deviates much from the quality of v0.1.
https://github.com/lhorie/mithril