Wife's restaurant had a Vita-prep (commercial) and Omni...that is until she banned frozen drinks ("Its an English pub, dammit...blended scotch is all you'll get here, if THAT. Want a frozen drink? Carry your azz to Applebees"
)
I think you can find an Omni for around $250 and they are just as powerful.
OMNI Blenders - Call for Best Prices on Vita Mix 4500, Waring 1200XT, & Blendtec HP3A Blenders
But you can find refurbed Vita-mix's in the $350 range that look as new and have the same 7 year warranty. New oone's are being advertised for $399.
Interesting info here on a variety of blenders depending on use:
http://www.consumersearch.com/blenders/best-blenders-overall