I've chimed-in on so many 870 threads that I've lost count. THIS thread reminds me of the discussion about what dog breed bites people the most. The answer to that seems to be labs...but because they are more prone to biting, or because there are so many of them around it's bound to skew the results? Answer? Door #2. So, while I'd never say there are no 870s out there that have problems...I WOULD say that I must be the luckiest 870 owner out there. I've had a bunch of them over the years, Wingmasters...Express...Police...and NONE of them have had feeding/extracting/ejecting issues. I have worked on a few Expresses belonging to friends/family, mostly stuck choke tubes...but one was an extraction issue because of a rough chamber. All pretty easy to remedy. With respect to the finish on the newer Expresses...no, they're nowhere near what a Wingmaster is (regardless of vintage)...but an ounce of TLC eliminates any concerns there. At least in my experience owning one for maybe 10 years now. Every time I hear the "surface rust" question, I wonder what level of care people give their guns and more importantly, whether or not they'd treat a $1,000-ish Wingmaster as poorly as they would their Express?
I'll leave it with this~a good friend of mine is an avid duck hunter, and bought an 870 Express Magnum for the job (synthetic stock). Worked perfectly until one day...his boat capsized and the gun sank to the bottom of the lake. I spoke to him soon after, and he'd managed to recover the gun a few days later. I asked how far he broke it down to clean it up and his answer suggested more work needed to be done. I coached him on what to do, what to check...he emailed me the next day and thanked me, as there was water/debris in some spots he hadn't imagined it could get. Everything dried, lubed, reassembled...and has worked perfectly ever since.
Bottom line for the OP~they are great guns, real work-horses...and most issues (in my experience) can be remedied with a little YouTube time and a little elbow grease. Isn't that the kind of gun most people would want?