I got one for The Defense. I wouldn't buy again if I could. I will buy again, in the future though, once they get the problems fixed.
Right now the biggest is that you can't change the audio levels of the sound FX and Tobi's voice, so in order to hear Tobi as loudly as the stream, you have to turn it up and are stuck with really loud sound FX. This is even worse when Tobi casts with someone that speaks softly.
Also, the animations were noticeably out of sync. I think they will fix these problems soon though, and then it will be really great. Being able to see exactly how the pros build their heroes with items and skill builds is amazing.