Hmmmm..... Well now, Mental Ray was used to improve capability! Improved capability in rendering, etc. = slower (relatively speaking). Unfortunately for you the average user does not do as much rendering as you and is more able to accept the speed -v- quality trade-off. On the up-side, typically the first shot of anthing from SW (specially something that appears in an SP rather than the intial release) is slow and limited, then sees a major improvement at the next full release. This is stated policy to get stuff out ASAP to you and see what you want to do with it. So tell them - nicely - and as specifically as you can through the enhancement request process on the support web page. Then keep your fingers crossed. Having said that, it would have been nice if they could have supported PW1 a little longer in parallel. Probably a licence agreement issue - those business types are killing us Engineers again!!!.
3/4 of all the Spam produced goes to Hawaii - shame that's not true of SPAM also.......