I have never really been happy with a pickup sound on an acoustic mandolin--although Richard is right, you can run it through a bunch of effects, have a lot of fun and make very cool sounds. (The late Willie P Bennett had a mando setup like this with Fred Eaglesmith, it worked in that context!) I have gone that route...but...

A year or two ago I invested $200 in a Shure SM-137 condenser mike, and it has just made my amplified life a whole lot easier. (There are two settings; you set it to the less sensitive one for live performance). Would recommend that item to anyone who doesn't like pickups, or doesn't like messing around with cables. I play it in noisy pubs, no FB issues.

Another keeper is my Peavey Ecoustic 112 amp--great sound really with full EQ on each channel. I can run the SM137 through it if I don't have a full PA. I see there's a newer generation of Ecoustics, the 208 has 2 8-inch speakers in a more compact package, which I would like to try out, but at about half the price, it lacks the professional features of the 112--doesn't even have direct outs.

All in all, the SM137 is the best piece of sound gear I've picked up since the Ecoustic (about ten years ago).

W-O
Whatever works!