If we say your budget it ~$1K +/- 200 (the Eastman 515 and 615 new prices) you have lots to consider. I like the Eastman mandolins very much myself. I got mine from Gianna Violins and Stephen Perry did an excellent set up. My only grudge with the Eastmans is the very small frets (I like larger frets I've discovered) and others feel the neck is narrow. Mine has a flat fingerboard. Other builders like Rigel and Breedlove are known for their very comfortable radiused necks.
A good dealer who will set up an instrument and listen to you about what you want rather than how much they can sell you is key whether you go Eastman, MK, Kentucky, or used from other builders. You can get a pretty decent used A style for that kind of money too. don't let body shape or headstock logo drive your decision. Let your ears and hands decide if possible.
There are two things to aim at in life: first, to get what you want; and, after that, to enjoy it. Only the wisest of mankind achieve the second. Logan Pearsall Smith, 1865 - 1946
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