I've only recently sold both an X3 and an X5 but only because I wasn't sure where the repair situation was heading not that either ever had any problem.
Paint finish/build/waterproofing/light weight was and is still better than the majority of modern detectors and my X5 could match or beat the performance of the Tejon on coins and good performance wasn't so dependant on the conductivity of the target.
On the negative side there was always a lack of coil sizes/types (3) and the fact they are no longer produced meant no third party coils. The discrimination was also too narrow for easy European use as there was a set point where depth dropped off rather to quickly if you set a fraction above it and iron was a problem if a fraction below.