This is the 1.000.000 USD question, which one to buy for media streaming and use of XBMC.
This is mostly due to 2 things, first is that these boxes are still not 1080p approved (you will need to experiment with several kernels that claim to have this output), and second is related to their power. They cannot play 1080p content, not even 720p content without the H/W acceleration.
What does this mean in practice? Well first is that even if you have a flawless version of Android (stable and 1080p content on it), you still need XBMC (in this case) to be able to H/W decode the content, or else you are unable to use it properly for any HD content.
The good news is that XBMC is about to release a stable version with the promised H/W acceleration, however its not out yet.
Now for the options: If you want good streaming, you need a reliable network connection, and unless your router is just next to the Android TV stick, you'll need a wired connection. This is not normally a problem, just be sure to get a true 100Mbit USB adapter (if it is not already built in), as some of them are only 10Mbit which is a bit slow for HD.
I myself bought a Tronsmart T428, as it has both 2.4Ghz and 5Ghz wifi module. However the available ROM's are not that many and I still can't use it as a daily driver for my media needs.
Another thing that you might consider is how to control it. A good remote will make or break the deal, as it's not easy to navigate android without the touch input. I sometimes us a mouse and keyboard (and it works quite well), but for HTPC purposes it's not the best. I also have a Mele F10 which is not bad, but the new version is well worth the extra (Mele F10 pro).
Good luck with your quest. If I were you I would wait a little bit until the new XBMC stable version gets out (12.3) and then see what others are using.
Hope it was helpful.