I just purchased a Kuat NV rack, 1.25 receiver version. It has the same advantages as the Yakima Holdup listed by simonaway427 above, plus:
1. All aluminum construction, for relatively light weight. Note: It's still a heavy rack.
2. Comes with integrated repair stand, called the "Trail Doc". This is a unique feature.
The 2" receiver version will have an optional add-on to hold more bikes -- not yet available.