What are the gears on the cassette? I think I would refer to the 50/39 chainrings as a "non standard compact.". I have a 52/38 on one of my bikes and always have to explain it.

My opinion on the 9 cog versus 10 cog is this: I would prefer the 10. Because there will be less change between cog size, you should have smoother shifting and more ease finding the "right" gear. It's also getting a little harder to find 9 speed cassettes, (not terribly hard but not as many options). But honestly I wouldn't rule out a bike cause it was 9 speed. However I might rule out a bike that had lower components than 105.