Songbob said,"For string-bands, A's work well enough. In a bluegrass band, at full roar, you may need an F, and maybe even then, a pickup." Sacrilege!!! Bluegrass is one of the few places where we can hear music played through mics and making an acoustic sound. The last bluegrass band I played in used only one condenser mic most of the time.
I agree that f-hole are preferable to an oval hole when playing bluegrass with a banjo and fiddle, but I still feel that a good A-style mandolin is as good as a similar quality, but much higher priced F-style.
I own an Eastman 605 (A-style f-hole) and a Washburn Country mandolin (Two point oval-hole). I play the Eastman for bluegrass and the Washburn for Celtic. When it comes to jug band, blues or other styles, it's a toss up.
I do have an old 1970ish Ibanez that has had a pick-up installed and is stung in a high-strung tuning. I rarely use it out of the house.