I have an Envision EN-LM500 Professional Series flat-panel monitor attached to my Amiga 3000T. My graphics board is a GVP Spectrum and I am using the P96 driver. My settings are 640 X 400 res, 16-bit color, 60 Hertz. There is no motion blur at all. Great picture and color. The only negative thing I can say is that the picture is not as crisp and clear as a CRT monitor.
Make sure that you are not trying to push the monitor beyond what it can handle. You have to remember that these old Amiga computers are not modern PCs or Macs. So, I have found that it is best to treat them as vintage computers. It is best to stick with the lower screen resolutions. Never go beyond 1024 X 768, you WILL have problems if you do. At least this has been my experiance.