I run a small single site trunking system, average daily users 80-100 with a total of 400ish subscriber units registered. We just replaced our old Harris core with a VIDA Excite last year, and are looking to have the RF site (currently MASTR V) replaced soon as well, waiting on funds. Most of our subscriber units are still Motorola (XTS/XTL 2500, APX 7000, 8000, SRX 2200), with some Harris (XG-100M, XL-200P) scattered in that were purchased by functional managers for our various activities.
Looking towards the future, our plan for the near term is to stick with the Motorola APX ecosystem for subscriber units because we already have a lot of the gack, and some of our sections "need" Moto for interoperability with the city/county system that won't "support" (give up control of/pay software licensing for) anything else.
My experience with Harris and their vendor (Eastern Communications) during the core replacement was not great; we will probably use them for the RF site as well just to rip the band-aid off and get it done. We tried looking at alternate vendors, but the costs ballooned. For subscriber units, I am not a fan either; when I first arrived, we had XG-75, XG-100, XL-200 portables and all three had different batteries/chargers, and 2/3 used the same antenna connector or programming cable. We've phased out everything but the XL-200, and the failure rate is much higher than the Moto counterparts so they will probably go away eventually as well. The XG-100M is also a PITA to key/program when they're buried in a vehicle console, whereas everything can be done from the control head on a Moto.
However, if the current APX series goes away in favor of the N/NEXT, then we'll be at a crossroads where we can entertain non-Moto subscribers for the users that don't require interop, if we have to buy all new stuff anyways. We don't need smart-phoney features; on our SRX 2200s, we got Model 1.5 with top display only; some of the users who had APX 7000 Model 3s didn't even know they had front displays because they never pulled them out of the holsters. Interop users would probably need at least a basic front display, for system/zone and scan functionality.
I've used iCom and Kenwood at another agency and was happy with them, and we do have one user group with EF Johnson on site using conventional frequencies. I'd like to try them on the Harris system with OTAR, but the big obstacle is getting our system key in whatever format is needed for their programming software. I tried contacting EFJ/Kenwood but they never got back to me. I would need to have samples in hand to confirm all the functions work with our system before even thinking about a purchase decision, since Harris will only offer support for Harris and Moto subscribers.