For Motorola, parts are available and abundant, and I have had relativly good dealing with Motorola support.
EF Johnson has less common components and parts, and being part of the JVC/Kenwood/Zetron group, I have had many issues with Kenwood and Zetron support. Response is always, upgrade software, pay for additional hardware and licenses, yet these solutions often do not work.
I will stick with XTS5000 radios, as they work, I can get parts easily and do not have to listen to support personnel that have no clue. Online forums have a lot more information as well, since the XTS5000 radios have been used by many in public safety, fire departments, military units and others.