Don't know if you're still looking, but my UD5 is great. The SB went out on my first one, but it could be the Cosmos S had a bad front panel. It worked great until a few hours after I put it in the new case and the front panel is still problematic. Anyways.
The heat sinks seem to work really well, my NB and other (as yet unknown) temps hang around 36~40. Never seen them go over 40 and that's with 1 240 Rad blowing from the bottom of the case and 1 360 blowing down directly on them (both in push pull), that does include the mesh side panel which I'm sure relieves a lot of heat. A lot of people reported Vdroop problems (which appears to be a spec for AM3+), but my Vcore set at 1.575 shows as 1.616 most of the time. (Running the F5 bios). Another + (if you use a large heat sink) is the RAM will go in the 2 and 4 slots (starting from the processor) if you only have 2 sticks. Also be aware the UD5's top PCIe 1x slot is almost useless because of the NB heat sink. The PCIe x16's are well thought out though. The 2 full time x16 slots are spaced well for dual slot cards/water cooling. And of course sleep and charge is uber nice!
Hope this helps.Edited by billy66bare - 9/3/11 at 8:18pm