The Seasonic is better because it independantly regulated, the Rosewill is group regulated.
It uses Japanese capacitors (IIRC the Rosewill uses Taiwanese caps).
Like you pointed out it is also more efficient.
I'm worried about your choice in CPU, what do you intent your build for?
Hah, I'm worried about it too now, but unfortunately I already bought it.
This computer will primarily be used for surfing the net, playing movies, and gaming as well. It's going to be kind of a "jack of all trades" HTPC.
I know now that I should have gone the Intel route, but I saw a great price on the 8150 and naively based my decision on the Passmark CPU Benchmark chart versus the practicality of what I wanted to do.