A few months ago, I bought a Google Nexus 7 tablet. I like to wait until I've used a device for a while before I post my experiences of it, but the disadvantage of that policy is that now the tablet I'm talking about has been superseded. That said, I'll pass on my comments anyway, since they may still be helpful to others considering their future tablet options.
My driver for getting this device was two-fold. I got an Apple iPad just a couple of months after it first appeared. It's been a constant companion, but its age is showing. It's not just that it cannot run anything newer than IOS 5 (that's not a big deal to me), the major problem is that many websites will crash the browser these days (which I gather is due to memory limits). The second rationale was experimentation, I wanted to try Android  and also try the smaller 7" tablet form factor.
On the whole I really like the nexus 7. The base Google UI is a touch better than Apple's. I miss the cross-application back button when I go back to the iPad. I also prefer Android's approach to completion in typing where they give you three words to choose from and don't automatically complete with the space bar (which regularly annoys me with IOS).
My feelings are more mixed about the 7" tablet size. I find that most of the time I mildly prefer the 7" due to its smaller size and lighter weight. However some of the time I strongly prefer the 10" size because of the bigger screen. There are times - some websites, pdf documents, or books with code or graphics - when that bigger screen is essential. The consequence of this is that despite the advantages of the smaller size I end up taking the 10" device on my travels for those occasions where I need the larger screen. If I could only have one tablet, it would have to be a 10", but I do use the 7" more often at home.
The other downside to Android lies in the applications. There are some nice applications for IOS that I can't find alternatives I like on the Android. To be fair this could be due to familiarity and a need to spend a bit more time searching. I need to put more effort into checking out what's available before I decide whether to use Apple or Android when I buy a 10" device to replace my iPad.
1: I first got an Android device at the Google IO conference in 2009 (where Rebecca and I spoke about cloud computing). This was what's since been called the Google Ion. I enjoyed having a smart phone and the experience led me to upgrade my phone account to handle 3G - but the only way to do that was to get an iPhone, so that was the end of that Android experience.