Just my 2 cents...
I've owned a 536HP for just over a week now. I purchased it from Advanced Specialties here in NJ and received a unit with a 48XXX serial number. So far, so good, but I'm a bit disturbed by the numerous problems other owners are experiencing. Still, the sensitivity seems to be very good, P25 performance is fine, and I like the ease of programming with the Sentinel software.
I've always felt confident buying Uniden products. My first scanner was a BC-140 back in 1988. I've purchased many Uniden (& Radio Shack) scanners in the ensuing years, including the 210XLT, 890XLT, 895XLT, 780XLT, & 996T. Not one of them gave me any issues or failed to perform as advertised.
Hopefully Uniden will work out the issues with the x36 radios and they continue to introduce new, innovative products. I would hate to see them pull out of the scanner business altogether.