Despite being a technical dummy, I found Alexandria easy to work with (But that might be just because of WP interface). Nevertheless, it immediately caught my eye while browsing available free template selections. This might well be due to its blue default display, which happens to be my favorite color. I also like the crisp graphics and flexible customizations.
The main drawback I see so far is apparently difficult navigation and unclear instructions for many tasks. However, that might be merely due to my own technical ignorance.
All in all, though, no matter how you look at it (no pun intended), Alexandria offers a lot for the price tag of $0!