A problem they both have (and SSC's regular spidey) is they don't have pattern on the suit. It would have made the pieces a lot nicer and more accurate.
This image is from Sideshow's Spider-Man 3 product gallery:
One thing Sideshow does infinitely better than MR is provide many photos of the product from different angles to help you make your decision. The only thing I've seen from MR is 3 small photos that don't give us forum junkies enough material to scrutinize.
I wasn't really interested in any of the Spider-Man 3 products, but I'm really considering getting this Spidey statue from Sideshow.