I do not have nor have I ever been aboard a 36 Express. I have owned a Mainship MKI and have been aboard many other models. I have also visited their old plants when they were in production in both St Augustine FL and Midway GA.
You may get a better response in the Mainship section, I believe there are a couple of 36 Open owners there.
Mainship built thousands of boats, ranging from the 30 Pilot to a 47 Motor Yacht. Most were Trawler types or Motor Yachts, the 36 Express one of the few ventures into an express cruiser.
Typically on any Mainship your will find value, they are not considered "top of the line," more like a Chevy than a Lexus. The build and engineering is good to very good, the choice of components as good as a top brand.
Engines, steering, controls, pumps, plumbing, etc are a place Mainship did not cut corners. What you get is straightforward sound build and engineering that works without a bunch of frills and foo foo (technical term)