I've been in situations where we used a MoMarsh boat as a layout on Kentucky and Barkley. The first year we had the boat in open water in snotty weather and some 2-ft+ chop, and it is not my first choice on places to be - you definitely want a life jacket, radio and a tender boat. No spray curtain means that you will be taking some water, so a sponge or bailing cup would be advisable. As it turned worse, the strategy was to "scrunch" into the downwind end of the boat to raise the nose and keep water out.
We also discovered that the profile of the boat - that is, not being a rounded "hump" like an Erie-style layout - created an issue for the divers, and in the chop the boat would bounce in the waves.
Maybe this sounds too negative, but I guess what I'm really saying is that if you exceed that for which the boat was designed (any boat at all), forget it. The MoMarsh is a damn fine boat that can be used as an open water layout, and I would not hesitate to gun out of one on Barkley or Kentucky again, but its limitations are that you need to watch the weather, and on the lakes (like Kentucky and Barkley) where layouts are becoming more and more prevalent, the boat will flare some birds that an open-water layout will not. If this is going to be your "only" boat, where you paddle out onto broadwater with your decoys in it, set them, and hunt, I'd do some planning, no different than any other trip, but with the specific boat in mind.
For flooded fields or smaller rivers/creeks I would use one, but would want to be aware of current, debris, rocks, etc.