Bookshelf speakers for $500ish

I'm looking to upgrade my Dynaco A25s to something more compact and modern.

They will be amplified by Marantz 2238B, and I'll be listening to acoustic jazz such as Bud Powell or Miles Davis- a lot of piano trios and small groups with horns.

The room is 10' x 12', and I won't be able to mount them on stands, or be more than a few inches from the back wall.

Budget is $500 or so. I like the idea of buying used, but I'm not up for a very long hunt. New options I'm considering are KEF Q300, B&W 685 S2.

Thanks for your help!