I can only go on my 30 years providing PA systems run on substantially temporary / generator based power systems. Early days were Crest P001 series ( mostly 8001's and 9001's), then moving to Lab Gruppen and more latterly Powersoft. The current models ( we are mostly X series based) have PSU's that will run on SPN+E, 2P+E or 3P+E with a very wide range of voltage acceptance without a loss of headroom on the audio side. We have FAR fewer issues with mains systems now then back in the Crest days of the 1990's - this may be in part due to better temporary supply design, but looking at metering on our racks inrush is a fraction of what it used to be, power factor and harmonics are also much reduced and general reliability is far improved. I certainly wouldn't wish to move back to linear PSU's, and being able to hang these large amplifiers ( 8 channels, 40Kw on a 12 dB crest factor) over 3 phases is a real advantage on larger systems, makes balancing much easier. Im quite sure this is not likely the case with cheap and cheerful SMPS units, but that's not the fault of the technology, just poor design. The PAM's were mooted as a possible replacement to the crest amps. along with RAM audio from spain ( they sounded great as did the Ecler's, but were very prone to failure, worse than the PAM's) but in the field the Labs proved much more reliable - and to be fair the Ecler's were likely more suited to installation use.