I'll jump in with a hunch. I think the reason you see posts about the 11-87P is likely due to use of low-recoil loads, possibly (haven't really tried to evaluate it) aggravated by short barrel lengths that affect port pressure to a greater extent than longer "sporting" barrels.
IIRC, there is even a Remington FAQ that says, in more or less these words, "we don't recommend low recoil loads in the 11-87P and the gun shoots so much more gently than a standing breach shotgun that you shouldn't need to use them." Some 11-87Ps run fine on low recoil, others seem to bobble.
Detractors notwithstanding, it is a very fine design and it's very well made. If you do not intend to use low recoil ammo, or if you're willing to test low recoil loads and live with the results, it is a very good choice.