P5 is apparently still very slow-- it may be a bit more stable. I'm going by comments from friends and what I've read in the beta forum. The slowness is not just rendering but also posing and exporting. How powerful is your computer? P4 with ProPack, which I think is all you can upgrade to, can get by with 1G or less processor. P5 seems to really need 2G and a lot of Ram-- a gig probably. The benefits of transparency is huge and you get that in P4. The MIl like Vicki and MIke figures are also only P4 compatible as far as I know. Emily