I LOVE my Maven C1 10x42's, but will be upgrading to the B2's as soon as I can get the wife on board. The C's are a SIGNIFICANT step up in terms of quality compared to my previous optics (broke college kid running cheap Leupold BX1 McKenzie's for a few years) and compete handily with anything on the traditional retail market that goes for about 2-3 times the price. Having said that, the B2's are just go good of a value to pass up one day. Until then, the C1's will run circles around the optics anybody I know runs, but the B2 just lets in more light and has a better field of view.
The AK prism in the B2's is definitely worth the upgrade, unless you already run Swaro or Leica or high end Zeiss. However, anything less than that, and the Maven will outperform them ten times over. I'm with everyone above, I would buy the B2's this year, save for one more year, and buy a good spotter in the next year or 2. Buy an S.1A to match the custom B2's you order!
FWIW, there's a thread on here for a good pair of lightly used b2's for like $800 right now over in the optics classifieds. I'm working on my wife right now to try and convince I need them more than we need to re-landscape the front yard, but if I don't get them, someone should snag them up! I think the seller's username is Parshal?