I would agree that the Whisperlite Int. is possibly the best stove ever made. I have had mine since 1997. I have never had a problem with my stove. It has never clogged on me, and if one doesn't over pressurize their fuel tank, this stove can sort of simmer.
However, this is my third pump for said stove. My original pump lasted many years before it developed two cracks in the body, near the control valve. So I bought the "new" design as a replacement. I was able to use it a few times, like twice, before the o-ring on the control valve went bad. So I bought a $30 maintenance kit to replace all the o-rings, etc. While putting the pump back together, I overtightened the control valve, and sheared off the plastic fitting. My Bad. So, this is my third pump in 14 years.
Advice: Be gentle when maintaining the pump, they are not 'bombproof.'