Haven't tried Arthemia. But, I have StudioPress, it's a great theme, but a little complicated to work with. Personally, I like both FlexSqueeze and Thesis better than Studiopress. HR
Studiopress Themes are pretty Confusing for newbies. So if you are new into this, better go with Arthemia theme.
I had the Arthemia Premium on my techie blog Best theme so far and it gives me the professional & credibility look!