Yeah, they "twang". My son has one for his G22/.40, and it twangs. Twangs like a Daisy Red Rider. He has 1000 rounds through it, and if that's the "worse" it gets, let'er twang!
So far, it eats anything its fed. Dead-nuts accurate out to 150 yds. with factory power rounds. The red/green dot sight they sell is very effective.
And the weight.... They're heavy out front. Heavier than other "black rifles". No problem though, punching out 30 rds at a time. Don't even notice the weight. You can slim it down some, if you pass on all the accessories hanging on the front (rails, light, etc.).
Life is tough. It's tougher if you're stupid. -- The Duke