Sumner
I had a 17. It was generally very acceptable quality of build, and a descent sailor. Better than an o'day 17, but not as good as say a 470. It was a day sailor, pretty tough, when knocked down it will take a little water in the cockpit, but not enough to endanger you.
The Sumner 19 I see on line looks like similar lines, but with a little cabin. I think that would adversely affect the sailing qualities of the boat, getting toward piggish with the added weight up front. A mariner 19 might be a better choice for a small cabin trailer sailor.