I have 4 atv2 two were upgraded and two stayed on 5.0.2
The upgraded had some freez problems on xbmc and the other two didn't had this problem
Therefor I think that if you have the option, stay with 5.0.2
The difference is not that much big
I have two aptv2 and both loving the newest jailbreak and update. Why bother with aptv3 when it was never promised to jailbreak. A nice black paper weight u have!