We have around 300 of the 2-knob 4000s and 30 1-knob earlier versions on our system. Since the OP did not advise what his/her intended user is, I will assume public safety.
My thoughts on the radio: it's about the same build quality as an XPR7550. A solid business class radio. It lacks RF connections on the UC, so forget using an APX PSM. Audio output is a little lacking at 500mw through the internal speaker, better with an RSM. Pretty hard to hear one on the side of a busy highway with traffic rolling by.
Battery life in a trunking environment with the standard NNTN8128 is around 9 hours before you're getting a low battery alert. Opt for the larger battery if your agency runs 12 hour shifts.
Display is hard to read from an angle. Can't tell any difference in RF performance between these and the APX6000's and 8000's we bought as part of our purchase. They all seem to have great RF performance as can be expected.
and contrary to popular belief, there is no "XE" version of this radio. Motorola made a 1-knob version, then the 2-knob came later. The 2-knob does have a thicker control top but it is not designated as an "XE" model and certainly does not have the same IP68 rating as say, an APX6000XE or APX8000XE. So I would not consider this a radio appropriate for IDLH or fire use.