I recently aquired an XTS5000, and I wanted FPP on it. I am glad I have FPP because if I ever need it, it's there. I personally enjoy having that end-user flexibility in a quality radio. As those who replied before me mentioned, there are drawbacks. There's also some that weren't mentioned. Here are some FPP limitations I have come across:
1. Maximum of 15 FPP zones. All other zones must be non-FPP.
2. All FPP zones must be consecutive. You can't have an FPP zone, then a non-FPP zone, then three more FPP zones, then another non FPP zone, etc. All the FPP zones must be "next to" each other.
3. You cannot move zones around; not even non-FPP zones. *
4. You cannot move channels around; not even non-FPP channels in non-FPP zones. *
* I am under the impression both of these things CAN be done in non-FPP radios, but correct me if I am wrong.
5. Each FPP channel must have its own personality. You cannot share FPP channel personalities with any channel other than the one it is assigned to.
5A. This eats away at your personalities really fast, for you only get 255 personalities. If you use all of your FPP channels, that's 15x16 = 240 out of 255 personalities.
6. All FPP channels MUST have the same MDC system and Astro system, and these systems cannot be shared with non-FPP channels.
7. You cannot delete an FPP zone. You must make it a non-FPP zone, then delete it. If you want to delete an FPP zone between other FPP zones, you will need to make all of the zones adjacent to it in one direction standard zones before you can delete it since you cannot remove FPP status from an intermediate FPP zone (see restriction 2).
8. Trunking and FPP aren't compatible. You can have one or the other, but not both. You can also have neither.
9. Each FPP zone can only have 16 channels. No more, no less.
All of this means programming takes longer and requires a lot more planning. If you need to make major changes like rearranging channels or zones, it will be a hassle so plan ahead and configure your FPP radios right the first time!
For me the flexibility (after programming is all said and done) is worth it over all of these restrictions, but to each their own. This list is also likely not complete - it's just what I could think of off the top of my head. Feel free to add or correct it. ^-^