I have the 2190uxi and can tell it is by far the best monitor I have experienced, and have compared it to the ACD's and spent sometime with another fellow who owned the Eizo CG210 at almost twice the price at the time. We both concluded the NEC 2190 to be better. From what I understand the xx70 series while still a good monitor is just not in the same league as the xx90 series nor was it intended to be. The 90 series uses the S-IPS type of panel but the 70 I would guess might not. Also I was told by the Tech Reps at NEC the 19 and 20 inch versions of the 90 series use a LG Phillips panel, while the 2190 uses NEC's own proprietary panel that supposedly is of a higher standard. Still I have no doubt you would be very content with the 1990 if you can get by the smaller screen size. I have heard some good things also regarding some Samsung monitors but do not which model numbers to tell you to look for.
Hope this helps