I have pleasant memories of the old Scientific kits too. But I also have some not-so-pleasant ones.
The big problem is that some of the kits had nice, basswood hulls and some had balsa ones. When I was a little kid my mother bought me a Scientific Flying Cloud. Not only the hull but all the other wood pieces (other than the round spars, which were birch) were made of balsa. As I imagine everybody in this Forum knows, balsa wood is just about the worst conceivable material for ship modeling. The kit was a box full of hopeless trash.
That one balsamic experience turned me off to Scientific kits for a long time. Years later, though, I took a careful look at a Scientific Golden Hind that was for sale in the hobby shop where I worked. This one had a nice basswood hull, basswood strips and sheets, and a handsome set of plans by none other than George Campbell. It was, as I remember, quite comparable to what Model Shipways, Marine Models, and Bluejacket were making at the time.
I don't know whether Scientific switched all its sailing ships from balsa to basswood at some point, or whether some particular kits were balsa and some were basswood throughout their history. Maybe somebody out there in the Forum knows. (A balsa Soleil Royal? The mind recoils at the thought.)
For the modeler of today, I guess my best suggestion is to find out what the wood material in the kit is before you spend any money on it. If the hull and other wood parts are basswood, the kit probably will be a keeper (especially for a less-experienced modeler.) But I wouldn't recommend a ship model kit with a balsa hull to anybody.
Youth, talent, hard work, and enthusiasm are no match for old age and treachery.