I've shot the 1201FP and I own a M1S90.
Cost: $459-550 (1201) vs. $750-850 (M1).
Action: same thing.
Controls: almost the same -- shell release lever/button placement is different.
Capacity: for some reason, all the 1201FPs I've seen have 6 shot tubes. The M1, with an extension, can have 5 or 7 shots.
Accessories: more for the M1. No dedicated Surefire Responder for the 1201FP (the 1200 model doesn't seem to work). The "factory" pistol grip stock for the 1201FP I believe was made by Choate. Most 1201FPs I've seen come with rifle sights, but I understand ghost rings are available.
Reliability: both my buddy's 1201FP and my M1 (and the M1s of two other friends) have been totally reliable with light and heavy loads. My M1 is weighed down with a Surefire Responder 617F and it still works perfectly with light trap loads and reduced recoil buck/slugs.
I don't think you can go wrong with either one. High-profile trainers speak well of both guns (Farnam for the 1201, Suarez for the M1).
Justin
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Justin T. Huang, Esq.
late of Kennett Square, Pennsylvania
