I've sailed a couple of trips in company with a Scamp. I agree the Scamp is quite slow compared to the CS. It is also fairly complicated to build, especially compared to the CS boats. A couple of folks from a large a reputable kit-making concern that will otherwise go unnamed stopped by our volunteer shop and saw the Scamp that is underconstruction there, and has been for quite some time. One of them said, "All that work, and still all you have is a Scamp." I agree (and agree with similar comments above).
I, too, have been attracted by videos of some of the other Welsford boats but those, too, seem like bigger contrustion projects than a CS. But I think all the added features probably make them very seaworthy.
Attributes of the Scamp, at least as I understand them from the companion mentioned above: It has the little cuddy that helps make the cockpit into a snug one-person sleeping area, if you have right tent. It will chug on through anything, albeit at it's own pace. I have seen it recover from a capsize, and it was very quick and essentially dry, done by one person. A capsize in a CS is a different matter, speaking unfortunately from experience.
The one time the Scamp really clobbered me was in a pretty fresh breeze, probably sustained >20 with higher gusts, and waves 1-2 feet, maybe a bit higher. My friend in the Scamp put in a reef and went plugging to windward without another care. I could not get to wind! I had put double reefs in both sails, and wasn't sailing the 17 very well, I decided later (too much luffing, not enough holding course). I think I would have been better off with a single-reefed mizzen in that breeze, sheeted in sort of half way. I talked to Graham later and got some tips. I think I will do much better next time. But that Scamp kept on plugging.
My friend in the Scamp is looking at a Longsteps as his next build, so he's sold on the Scamp ideas, but would like something with a longer waterline and more speed.
Wow, that came outlonger than I expected.