We had a major disaster with SP1.0. It was so slow and was taxing our EPDM server. There was some bug causing our server's CPU and RAM to spike causing massive slowdowns and it was almost to the point of turning off PDM in order to get work done.
SP 2.0 appears to have fixed that issue and now we are working smoothly with almost no slowdowns.
We are hesitant to upgrade to SP3.1 until we hear of any other feedback from users.