The newer DCH and DCX's are a bit faster as far as their CPU's, and may be more responsive. The DCX's support 3D, although that's a dead-end. It also support 1080p, but there are only a few OnDemand movies that support that, and they are probably 1080p24 (bandwidth is not that different from 1080i60). They also support a newer remote protocol called XMP (same used by the DTA's), but still also support the older Motorola codes. In fact, if you want the 30-second skip forward, you have to use the Motorola code, as I don't know if there is an XMP equivalent. It's also possible there are some non-Motorola DVR's being used (Pace?), but they are probably functionally equivalent to the DCH or DCX series.
The software used is the same iGuide, so it won't look all that different. X1 is a totally different beast with it's own hardware and costs ($100 upgrade fee and more) along with it's own bugs and quirks.