I used tango with my wife's TB and my Droid Pro, she could see me but i couldnt see her since i had to flip my phone to face the camera. The video was quite good, but the audio sucked, we couldnt hear each other.
Also, we used Qik for the evo 4g (different than the app in the market) i installed the evo .apk on the droid pro and the TB, video was better than tango's and we could also hear each other except it was very faint, another down side to Qik is that i was seeing my wife (in my droid pro) upside down...but she was seeing me just fine.
oovoo sucked....i uninstalled it cause it started to run the battery down plus the only thing icould do was record videos and share them.. no live video calling.
Definitely alot of improving needs to be done on these apps...