For new construction trailerable mini-cruisers, I vote for the Sage 17 or the West Wight Potter Voyager 20 as far as new boats go.
Jerry Montgomery was able to tweak many things on the Sage 17, which I think makes for a better boat than the Montgomery 17. It's a fractional rig, rather than masthead, so that makes singlehanded cruising a bit easier. It also has a very open V-berth that's easy to climb in and out of. 2 quarter seats that allow upright sitting headroom in case you are rained in the cabin. Lighter weight from a carbon fiber deck and cabin layup allows less ballast to make a stiffer boat. I've climbed around in one several times at the Annapolis boat show, and I love them.
As for the West Wight Potter 19, there are two versions right now, but they only show the original one on the web site. The original setup has a lifting keel, and compression post. The resulting trunk and post split the interior and make moving around a bit more difficult. On the Voyager 20, they have made a ballasted stub keel and centerboard like Precision, Sage, O'day 192/222. They have also incorporated an arch into the cabin top, eliminating the compression post. Finally, they have moved the galley from a split port/stb'd config, to all on the stb'd side. The result is a very open interior plan that's easy to move around in, and can even accommodate a table. I think it might be a bit stiffer as a result of more ballast in the stub keel, but don't quote me on that. Again, I have crawled around inside the new Voyager prototype at Annapolis, and I thought it was a winning design.
I always thought I'd eventually get a Precision 18, but I think it's more like camping in a backpacker tent. I find the quarter berths are somewhat low, so you always feel like you're on the floor. When my O'day 192 came on the market, I was very impressed how much more cabin-like it felt down below, compared to the P18, because the quarter berths and v-berth were higher than the P18. I'm hoping to get some good camping on the hook in the 192 this summer, so hopefully my opinion won't change. Also the P18 strikes me as being very sprightly, and somewhat tender, slightly more like a ballasted dinghy in feel, though not excessively so. I know some P18 owners that are a bit afraid of the way they like to heel, but that's a failure to trust the boat and trust the ballast. It's been an adjustment for me to go from centerboard dinghies to a ballasted boat - I have to remind myself that it's ok to heel, and she'll round up. Whereas in the dinghies, I'm makin' sure I don't capsize
Hope my opinions help,
Brian