I have no personal experience, only from the various boating boards I frequent. Over the years, I've heard nothing but good things about them, in terms of the company, and the fit and finish. Depending on the model, would put them in the same league as SeaRay, Chaparral, Regal and Four Winns cruisers.
I particularly like some of their layouts. Most of the boat makers that make everything from 18' to 45' have their specialty. You can't really judge a brand exclusively now, you have to judge by comparing models of each brand. I think Monterey is a class outfit. Depending on size, I'd compare them with Four Winns, Cobalt and Regal.