i have had both of these units, although actually sold them on. IMHO it seems like although they share many similarities they do distinctly different jobs.
the ultramizer is more of a mastering machine, it allows you to add compression and bring up rms of a track , limit it...for a similar effecy and then add the stereo enhancement etc.
the ultrafex unit is specifically designed to enhance the stereo image, boost the bass frequencies if required, and enhance the highs.
i personally found the enhancements offered on the ultrafex better than those on the ultramizer but since they actually are designed for different jobs it is perhaps harsh to compare.
if you are making tracks and wanting to polish them up then the ultramizer is a good buy, if you are just wanting it to run with a dj set up them i would get the ultrafex. its ability to brighten up tracks is great, you can even run it with your home stereo( if you have separates) to make commercial cds sound nicer.
if its for a mobile rig, have you thought about getting an EQ unit instead?
hope this helps. why not ask them to wire them up to a cd player or turntable in the store and listen to what they both can do.
