I got a Rogue mandolin from Musician's Friend.  It has been a good little instrument to get started with, but I think I would like a more serious instrument - although I am not ready to hit the $700 and up price tags.

Does anyone have a recommendation of a good instrument in terms of tone and playability?

Also - a few questions about models of mandolins:

Is the difference between an F and an A just visual aesthetic preference?

How about the oval sound hole vs the pair that look like Fs?  Difference in sound, or difference in taste?

Thanks,
Chris