What are the differences between the KT3 Ultra2's?

I've been interested in these boards and buy one soon(having no 1/5 divider sucks)

I noticed there are a couple of different models of KT3 ultra2's. What are the differences and which one is better?

Another question is, with the way the processor is positioned vertically, wouldnt it be difficult put on and off the heatsink with the power supply right above it? I'm looking at my current motherboard and I can't imagine how I can get a flathead between the heatsink and power supply.