I use the Spyder4Pro at home and one at my office - the puck itself is exactly the same as the Elite, but the software is slightly more limited (Elite has more features for multi-display averaging, color,backlight uniformity & user-configurable whitepoint values. Can also be upgraded to Elite software at a cost, if necessary). It's a good fit as long as you're not needing to constantly calibrate multiple displays. Perfect for home and small biz situations with a few computers/monitors max, and contains all standard gamma/whitepoints out the box.
As far as the MBPR goes, I gotta be honest here - I wasn't particularly pleased with the Spyder4's results for the Retina in my case. The rest of my displays look fine across the board, but the Retina (even after successive recalibration under different light conditions/viewing angles) looks just too yellow (with slight green cast) under the standard 2.2 Gamma/D65K whitepoint settings. I ended up simply using the default color profile (Color LCD) it shipped with, and while it's slightly on the cool side (blue cast), the whites/greys/blacks are much closer to that of my grey card when compared to the Spyder's yellowish profiles. Printed images (also profiled) are a closer match to default profile as well, though warmer just not to the extreme the Spyder4 was pushing. Again, this is simply my experience with it, I'd still recommend it as a calibration solution for most things, but I'd pass if you're going to use it to only calibrate the Retina. YMMV.
Hope this helps, even if just a little. 🙂
