If you want smooth movement stay away from the 250EX. I got two of them and just installed them yesterday. When doing slow scans these looked terrible. WTF was American DJ thinking when they made these?
However yes the seperate color and gobo wheels are nice, plus the mirrors are very fast. So if you only need these for fast across the room scans they are great. I also like the Digital LED controls to set addressing and invert Pan / Tilt. However another gripe I have about these is they are not very bright. They have an MR 16 bulb with a very small hole for the light to go through, This is one of the main reasons for the small projection angle.
I have these fixtures sitting next to some Venue Scan 250's. The venues are perfectly smooth and much brighter ( using the same bulb ). But their mirrors are a bit slow.
Right now I am trying to find all the used Mighty Scans ( no longer made ) I can, as those did it all, and used ones can usually be found for less than the 250EX