Hitch mounted rack for many reasons, the following being key: no height clearance issues, less likely of a mishap resulting in damage to the 4Runner, and/or bikes and a lot easier to load.
I went with a tray style rack because of the frame design on my Stumpy FSR, which would require an adapter or the bike to be mounted at an angle. I've heard incidents of the bike either making contact with the rack or another bike resulting in damage to the bike or the adapter not securing the bike.
I got the 2009 Yakima Holdup, model# 8002433. Watch for some retailers that sell the Holdup for less, most likely it's the '08, model# 8002419. The improvements for '09 are there's a pull pin to fold and lower the rack, rather than requiring the removal of a supporting pin and safety clip (similar to a hitch pin setup)--making it really easy to change the rack position, especially when bikes are loaded. The other is the StrongArm (the tire grabbing hook) doesn't rotate past horizontal preventing it from hitting the ground.
I looked at the Thule T2 as well, and I really the fore and aft and side to side adjustability offered by the T2. This makes fitting any bike super easy and eliminating any possible bike to bike contact. Both the T2 and Holdup have 60lbs per tray/bike capacity. However with the expansion for four bikes the T2's total capacity is 160lbs, 240lbs on the '09 Holdup and 200lbs on the '08 Holdup. Can't go wrong with either the T2 or Holdup.
IMO, tray style hitch rack is the way to go. It'll carry any bike regardless of frame design with ease.
BTW, seen some bike names mentioned. My next upgrade will be an Intense Tracer VP or Uzzi VP.
