I suppose there are, including the station I operate.
With me, it is a Christian station, and I hate to say it, maybe more prone to donations than other stations. Still, LMTTRR doesn't get the support that the Atlantic Sound Factory has for donation income (my perception-and ASF is not Christian or religion based), so my premise may be wrong.
As for advantages, you can play more what you want for your audience, and can get away from the charted music a little more. If you are playing oldies, then a little less of the mainstream oldie music, because your listeners like what you are programming. Also, there isn't a whole lot of money available for streaming stations, and getting advertisers on board may not make up for any donations.
If you plug, every half hour, and I mean, every half hour, for a week or so, you might find a loyal group of listeners that are willing to donate to your station. Don't worry so much as to how often you are making your plea, as listeners are fickle, and don't listen for long periods. Just keep plugging away, and see where it lands you.
My two cents worth, and your mileage may vary.
