Not that I want to compare, but I never had any trouble fast-forwarding or rewinding streamed content (SD or 720p HD) in Tversity. More specifically, I could seek at 1.5x and 10x no problem, and then I'd hit problems if I tried to go faster.
With PMS 1.3, I can only fast-forward at 1.5x and I can't really rewind at all. If I try to fast-forward at 10x, the entire stream freezes up and I am forced to press play and wait for 60 seconds, or just exit the video and start over again (faster). It's a minor annoyance, but I watch a lot of streamed TV content and I like to skip the credits/theme song at the beginning.
Off the top of my head, I can say that I've limited my bandwidth to 15Mbps and I've tried this on all the default transcoder types. I'm running on a P4 dual core 2.6Ghz with 2GB RAM.
Does anybody else experience this?