The problem with Bluebones is that it uses the most recent scan of a card. So if there's a grainy preview of something, bluebones will grab that instead of the existing, higher-quality art. We were trying out some Innistrad rares for our set, and printed out Geist-Honored Monk. Bluebones gave us a grainy preview of the Commander 2014 print instead of the Innistrad print.http://magic.bluebones.net/proxies/
Makes very nice proxies (minus the Magic Online scans that occasionally come up. Don't print the MTGO versions).
Print with a Horizontal Layout to get 8 to a page instead of 6.
You don't have to trim the borders, but if you do, they don't slip out of the sleeves as much at the top.
Source: have an entirely proxied cube because we have free colored printing here at school
Since then I just go to magiccards.info and choose the best-looking version of a card myself. M12 can look brighter and cleaner than M14, on some cards.
It should print 9 to a page - check your printer margins or turn on borderless printing maybe. I find it useful that they wind up slightly smaller than real cards; they can hide unobtrusively in a penny sleeve.