I bought a white evo that had 2.1 on it and there was very noticeable light leakage under the home key, and light leakage under the menu and search keys. Exchanged it for another one this past Thursday that had 2.2 on it and there is just the tinniest bit of leakage under the home and search buttons. It's hard to even see it.
On the one that came with 2.2 the power button and volume buttons felt a lot more stable to me, and I found the power button was easier to use as well.