I'm not real sure I am qualified to answer your question but I have experience with all three, well I just sold the 11-87 last month. The 11-87 was a police model with ghost ring sights so it was not used any longer since I retired and just taking up space in the safe.
I should state that the inertia recoil 12 gauge I have is of the Benelli M1 design, it is a Stoeger M2000 auto loader but I have shot both the SBEII and the Stoeger side by side and really couldn't tell much of a difference. They both seemed to whack me pretty hard with 3" #4 lead loads and the SBEII recoil was a bit disturbing with the 3.5" stuff.
I just purchased the Beretta Extrema II last week and I've only put a couple hundred rounds thru it so far. It isn't as hard on me as the SBEII or the Stoeger, recoil seems less but I wasn't shooting at anything just poking holes in the air with 3.5" stuff. So far it cycles everything I have put thru it. 1oz #8's to 3.5" BBB it just zips them things right thru no problem. I feel I can shoot the Extrema all day on the trap range and never complain of recoil, it is very smooth. Beretta does have the Extrema II with the Kick Off system, the price jumps about 200 bucks but it is supposed to significantly reduce the felt recoil and it still puts you in the SBEII price range.
Is it worth the money? Well, I certainly think so. I have had minor problems with other guns and when the geese come in and things don't work, it get's real frustrating real fast. My neighbor uses an Extrema and that thing never fails, one of the other guys I hunt with uses a SX2, it never fails and the third guy I hunt with uses a SBEII and it never fails.
I do know this, a gas auto guns felt recoil is way less than that of a pump. I had a Benelli Super Nova and fired 3.5" stuff in that. I might as well been trampeled by a herd of horses. Geez, I was sore for 3 days after shooting that thing.
Last but not least is the 11-87, that thing was one of the smoothest softest shooters I had and I would have kept it but the rear ghost ring sight base was milled and soldered onto the reciever and could not have been removed, so I sold it instead. I fired only 2-3/4" 00 Buck and slugs in that thing and it was a sweetheart to shoot. When I fired some 3" magnum stuff in it, it broke the extractor, so I question the reliability of the Remington with heavy loads.