It indeed runs surprisingly well (surprising is even that it runs). However, I would not say that it is usable.
Editing even the default scene (a cube) is painfully slow (2 seconds to switch between modes). Solid shading (in the editing viewport) does not work at all. Wireframe shading works fine (but still - too slow to be usable). Cycle realtime-rendered shading produces some result and does so in reasonable time. Again this does not mean 'realtime' time - forget using it for editting.
Backup your SD card and try the experimental 3D driver.
• Don't like the board ? Missing features ? Change to the prosilver theme ! You can find it in your settings.
• Don't like to search the forum BEFORE posting 'cos it's useless ? Try googling : yoursearchtermshere site:raspberrypi.org