My only experience of a sliding dropout was on a Kona Cowan Jump bike, quite similar to the paragon design I think.
A very clean solution to the whole issue of SS chain tensioning, and allowed the use of a QR hub, but I did find the brake side dropout (used with a 6” – Hayes HFX9) would on occasion move forwards; putting the back wheel on the piss, not ideal I’ve seen other designs with set screws, not sure if the paragons have this, it may help mitigate the problem, I’ve never heard of anyone else suffering the same problem so it may have been a one off…
Just about every proper SS solution involves some additional components/weight; ECC BB, Horizontal DO with a tugs, hanger mounted tensioner, BB or ISCG mounted tensioner, all have some added weight. The only zero weight solution is the mythical “Perfect Gear” if you can find it and live with it… realistically I reckon Sliding DOs come a close second to an Eccentric Bottom bracket in terms of neatness and function but it probably weighs a bit more, still weight saving isn’t the only consideration, mechanical robustness and simplicity is probably more useful that a ½ lb saving…