If you don't like the weight of the 870, you're not likely going to appreciate the BPS, either. They also have a steel receiver which is heavy and changes balance. I do have fond memories of a 16 gauge Ithaca M37 featherweight in my youth, but it had a crossbolt safety. It was not the best for the southpaw. I shoot southpaw due to an eye dominance problem, so yeah, that's a concern of mine, too. I like the BPS, but duck guns can get away with being heavy. I own, however, a M500 Mossberg and have been using them for the last 30 years. The ergos are awesome, ejection doesn't bother me, don't even notice it. Even if I shot right handed, i'd prefer the tang safety. The ergos are just miles better on the Mossberg as opposed to the 870 and the gun is lighter and balances more weight forward.
JMHO and YMMV