The zip broke on my Tourmaster Flex pants after a year but they were subjected to undue pressure (hey, they were a small!)
I’ve had Rev’IT pants for 12 months and a jacket for 18 months and had no problems. The jacket gets worn about 6 days a week, pants maybe 1 or 2. I also use the leg zippers each time I wear the pants as well as the zipping them to the jacket. The webbikeworld guys make a big deal about zips on jackets/pants and always point out when a company uses something like YKK. If Rev’IT is not your thing I’m sure there are other brands out there who use quality zips.