I bought a very early model XG-100P as a demo unit, as I was working with a corporation that needed an intrinsically safe VHF/UHF radio, but also sometimes worked with 800 MHz trunked systems at oil refineries and the US Coast Guard. This company had been using Vertex Duo/Yaesu FT-2070's for years, and the other option was to buy single band Motorola gear, having some people carry a VHF radio and another in UHF. The Multiband Harris Unity radio looked like a great deal.
However, there was the Radio Programming Manager (RPM) software, which required a dedicated computer for each software license.....very different than Motorola where the CPS (Customer Programming software) could be put on many computers. Many options are software dependent, and my old radio does not have all the features that a software updated version would have.
As others have noted, it is a big radio, but did take a few hits on cement with only slight scratches. The displays, especially the big one on the site is easy to read and shows a lot of detail. The Mission Plans are usable and would have been great for my employer at the time, as we could have a Mission Plan for "Marine VHF", "Coast Guard", "Refinery" or UHF and VHF in the same radio and Zone.
But, the biggest problem was the price.....they were expensive at the time. $6k for one radio was a bit much when they came ou, at least for corporations that did not get grant money. I paid the IWCE demo price of $1200, with a copy of RPM, cable and accessories. Then realized the limitations, having to provide a dedicated computer, authenticating with Harris corporation servers, much like registering a Motorola Entitlement ID. But, for amateur use now, and some monitoring of local systems, it works well, if you have the RPM software and programming cable, and a dedicated computer. Multiband a few years a head of Motorola, but only good as the price is now around that $1k with some wear and tear. I luckily do not have issues with my keypad or displays, but did have to replace a single pocket charger about 8 years ago....which was luckily cheap.
For the "cool" factor, they are great as in my part of the country, only federal entities could afford them. so, in many circles they earn "bragging rights" with amateur users, as being a high end radio. Or, someone may think you are a fed (good/bad?), and only those with military radios (AN/PRC-148 Thales or AN/PRC-152 Harris) will have something better to brag about, if that matters. With the APX8000 being available for a while now, and the APX7000's before that, you may get laughed at for spending the money on a Harris radio, if that matters. I'm keeping mine until it breaks and can't be fixed (probably can't if/when it breaks) as it works for my needs and still looks good and is serviceable.