It will never replace the wire but have you seen the new Finepart Micro waterjet? you can get down to a .008" Kerf and accuracy of +/- .0004"
We looked at a similar OMAX machine. The accuracy you mention is likely machine movement and not actual jet cut accuracy. The smaller orifices are very difficult to work with and very high maintenance.
actually the OMAX is just a smaller waterjet. This is a specially designed machine with a linear motors, Fanuc 31i control, Invar linear scales, www.finepart.com is the website
Still just looks like a smaller waterjet to me. It does not matter how precise the motors or scales are, there is only so much positional control you can have over a jet of water and garnet. Definitely a fine looking machine and one we might have considered a few years ago.