I have put thousands of rounds through my Remington 870 Express in the 21 or 22 years (maybe even 25 years) I have owned it. I have used it extensively for hunting, for quarterly qualifications at work, for tactical shooting practice, on my job (never shot it though while on the job except at the range), for trap shooting, and for fun shooting. Nothing, I repeat nothing has ever broken on it. I did once replace the magazine spring, but only because I lost the original, but that is a whole nother story, and I am not about to get into that right now.
I ahve also seen Remington 870s take the abuse as pool guns at the range on my job. Rarely cleaned, dropped all to often, treated pretty poorly - certainly not like an issue gun or a personally owned one, and always working.
I think it is one heck of a great gun.
All the best,
Glenn B