I guess I have been lucky. 6+ yrs and 17,000+ miles on my Keystone Montana and virtually no problems except failed microwave after 3 yrs and failed sound system after 4 yrs. No surprise with all the bouncing going on back there. I did replace the OEM tires with XPS Ribs after the first year.
As far as tires, there have been a number of reports on the Montana web site of Goodyear Marathon blowouts with damage to the trailer. And, with the return of the tire(s), Goodyear replaced the tires and paid for the damages. Don't remember any similar comments about Towmax.
A TPMS is a good thing to have. It will not prevent a blowout, but will alert you to a low tire before it has time go completely flat and disintegrate.