Ohms are direct market, so you have to audition them at home. Vann's is an authorized Mirage dealer and offers a 15-day refund period as long as the product is in original condition and is returned with all original packaging.
02-19-10: Branislav
Well, maybe one day I'll compare the two in my environment. Then I'll share my findings with everybody here on Audiogon...
Right now Vann's is offering the $7500/pair OMD-28 for about $3K/pair in black or rosewood. Pricewise this puts the OMD-28 at a decided advantage, because it should handily outperform the similarly priced Ohm 2000.
The OMD-28 and Ohm 5000 should be a good matchup, but Vann's pricing gives the Mirages a $3500 advantage.