Honestly, there's not much to say about Flash 10.1 on Android that you haven't already seen, given how hard Adobe's been pushing the Flash-on-phones message. There's a few things.
Why You Want It
A brief recap: Flash 10.1 is the first time the complete, ungimped version of Adobe Flash will grace phones since it's been re-architected in a way shoving it on a mobile device won't cause the apocalypse. Videos, Flash games, and yes, ads will actually work on phones with 10.1. The end result is that the internet you see on your phone will look a bit more like the one you see on a desktop, for better or for worse
Who Can Get It and When
"General availability" of Flash 10.1 is supposed to June 17. But Adobe warns "not all targeted platforms will be ready with Flash Player support at the same time." The targeted platforms, FWIW: Windows, Mac, Android, WebOS, Symbian, Windows Phone and BlackBerry. From what I gather, It's the first three that will actually see Flash 10.1 on June 17. (The iPhone is not on the list, as much as Adobe might want it to be.) The beta for PC and Macs has been out. For Android, the beta is out today, though you'll need Froyo 2.2 to run it, along with these hardware requirements (in the US, basically the Droid, Incredible, Nexus One or Evo 4G.)
What's It Like
So, we've had a Nexus One running pre-release versions of Flash 10.1 and Froyo 2.2 for a couple of days. The big caveat to making any judgments about performance is that the version of Flash on there is so far from final, hardware acceleration isn't enabled, meaning it's (theoretically) nowhere near peak performance. It also means even crappier battery life. (Adobe promises three hours using software decoding, but that's with nothing else running on the phone, and they asked us to "refrain" from installing any other software because the delicate nature of the pre-release Froyo and Flash, so we couldn't really do any meaningful real-world testing. But assume it will be much shorter, given how people actually use Android.)
Adobe loaded up the phone with a list of recommended Flash sites to check out on the Nexus One, like a Warner Bros. site, Nickelodeon, Kongregate (gaming), Miniclip and some others. Not surprisingly, they all worked, usually pretty well, but at worst, tolerably. The trailers on Warners' site look fine, exactly how'd you expect on a phone for something being streamed—definitely less clarity versus a native, locally stored video file, but better than you might expect. On the other hand, the controls in some games, like for Kongregate's site, felt a little laggy.
The irony is that a huge chunk of the recommended sites are "mobile optimized" or specifically designed for phones—which, at least implicitly, seems strange, given that the underlying premise of Flash on phones is bringing the "complete" web, including Flash, to phones.
Taking it outside of the recommend list produced some mixed results. For instance, College Humor's site and videos load just fine, well even. But at ABC's main site, it never quite managed to play video, though it looked like it was on the brink a couple of times. Hulu won't play at all, because it intentionally blocks mobile devices because of distribution rights issues. Adobe says it's the only site they know of that does that.
Overall, there's clearly more to be happy about than to hate—I mean, it's not like you have to use Flash if you don't want to—though it's got a ways to go before it's really ready, which indicates the enormity task Adobe had at hand: slimming down a beast known for bogging down full-grown desktops into something that'll actually work on a phone. They haven't done a bad job so far.