John, MS12 Platinum does support masking if by that you mean isolating, or cutting out, an area to work on or replace. You need to create a parent/child group of tracks and give the parent mask compositing mode. There is also a cookie cutter video effect which you add to a clip so you don't even have to create a mask track. However, MS doesn't have lots of premade Quickshapes to use as masks like MVP. Also be aware that MS12 Platinum is more extensive than ordinary MS12 which can be confusing.
The NewBlue titles don't work on my machine as I don't have sufficient GPU capabilities so you will have to tell me what I'm missing. Surprisingly the NewBlue effects do work despite the blurb saying they don't work with Intel, which I have. The MagicBullet Quicklooks also work. But I'm not into fancy effects. Movies to me need to tell a story not show off fancy effects.
MS also doesn't have a Transform adjustment like MVP but so far I've not found anything that I do in MVP that I cannot do in MS12 by some other means. And MS12 has many options in its menus that MVP doesn't. And when it comes to mp4 exports you have the choice between Mainconcept and Sony's AVC. I've found Sony's best.