Rainsport 3, used to have MPSS and trust me I don't feel disappointed after I changed to rainsport 3, and I don't potter about either. The MPSS are probably few percent better ultimately but I'm not pro enough to notice on the road.
For the back MPSS are £170ish, whereas the rainsport 3 are £105. Quite bit of price difference for minimal trade off, I've looked at it long and hard when I decided to change tyres, all the mid range like Falkens and Toyos etc are crap in wet grip, noisy and mediocre dry grip, but the new rainsport really impresses for the price. The Rainsport has good dry grip, fantastic wet grip and are quiet, can't comment on wear yet as I've only had them on for 1000miles but the previous version seem to wear well.