As a owner of a Hulk and METLE, I can tell you this simply is not true. My METLE out of box has been a great experience- no issues besides switch adjustment and my right sling once in a while is overpowered. Hopefully that gets fixed. With my Hulk it was a nightmare (and I'm a fan) between the shooter lane, widow ramp, trapped balls around Hulk, and insert visibility issues it was non-stop tweaking.
Overall Stern has nailed it with the quality of METLE- I do question the ball lock "block" behind the hammer and I get some airballs if I hit Sparkys feet sometimes, but these are small things compared to Avengers.