I should mention I have the VF700AlCu, not the VF700Cu like you guys are talking about, so you might wind up with better temps than me.
Idle with the stock heatsink was around 49/50 and now I'm around 42 with the fan on the slowest speed. Can't give you load temps or much more temp info yet as I only installed it last night and haven't had much time with it.
I mostly installed it for the reduction in noise. I have a Sonata II w/ 120mm TriCool Fan on the slowest speed and a CNPS7000AlCu on the slowest speed so it was the noisest thing in my case but now I'm back to being almost silent.