I think this is great. With so many companies jumping on the bandwagon (and a big name like nvidia), I think it's making it more and more likely that the idea as a whole will work - android being used as an open gaming platform, open to develop hardware and software for. Sort of like how PCs have done it, like having the 3ds being open for anyone to make a version of.
The more companies that try to do this, the more customers are reached, and the more viable the platform becomes and the more people start to think of android as a gaming platform. The main thing is I hope it will be easy to get a game working with all the various hardware out there. There really needs to be something to make doing so easy for us devs.
I'm a bit concerned about the quality of hardware - not from the current contenders specifically, but historically there are generally companies that make subpar hardware to undercut their competitors, like for example when Apple decided to let other companies make Apple hardware, there were a lot of clones that had issues, devaluing the brand and it almost tanked Apple. Similarly, the amount of garbage software for the Atari almost ruined the industry before Nintendo saved it specifically by having a closed platform so they could ensure some level of quality. With the Internet as prevalent as it is now though, it's a lot easier to research something before buying.
All these companies joining in also means that it's likely that we'll get a platform that is being updated whenever new technology is available rather than once every 5 years or so. Honestly, I think a regularly updated video game platform might be the thing the industry needs. It works great for iOS and pc - why not consoles?