This is great news for those who have struggled to get the client to install. (Unfortunately, my Moto Q still doesn't work with the new version.) Google didn't stop there, though. The new version is worthy of the 2.0 moniker in that it runs noticeably faster. I found that the Blackberry ran as speedily as Gmail on the T-Mobile G1 for e-mail searches, riffling through my 5.5GB of Gmail in no time.
I have tested Gmail for Mobile on about 30 different phones over the past year, and there is an obvious speed-up in the code, likely a result of the work Google has done in speeding up Java applets and getting Android out the door.
There's also a new offline mode, which points to a bright future for people like me (and a friend I know who works in the insurance business and relies on Gmail for Mobile) who lose their carrier signal on country roads. Now, you can still access all of your mail, reply to messages, and search your archive even when you are nowhere near a cell tower - Gmail just syncs it all up when you re-connect. There's also a way to save multiple e-mail drafts, and have multiple e-mail accounts on the same phone. There's also a few new shortcuts -- Z for Undo, K for newer conversations, etc.
I am a Gmail user on the desktop and on my phone. The one thing I'd like to see implemented better on mobile is labels. I know I can access them by wading through a few menu options, but I'd like to actually see them on-screen somehow, because I use them like crazy. Of course, Win Mobile users would also love to be able to use the client at all. Also, people are commenting on the official Google Mobile blog that version 2.0 is freezing for them on phones like the Nokia 2630 and N82, so be careful out there. (It works on the Nokia E71, one user reported.) I'm sure Google will work out these bugs, they almost always do, unless of course it is not a bug but a feature.