UFH takes hours/days to respond (unless you cook the floor). Rads take 20 - 30 minutes (usually).
If the UFH is a slave to the rad controls then you'll never get up to the right temperature, or you'll have to run the system such that there is no point having it and you might as well spend the money on fancy rads.
The biggest problem we have with UFH is with people installing it without an understanding of how to control it; and also when the homeowner expects the system to react almost instantly like their rads do and have scant regard for open windows and doors.
It is an expensive thing to screw up. But great if done correctly.