Opinion has been quite divided on the Studio Woodwinds library.
The extended individual articulations on the solo horns (horns up, stopped, etc.) are quite nice, and the four horn legato and sustain is much better imho than either of the solo versions. But yes overall the horns are a disappointment. The euphonium is also excellent (but only available in the pro version).
I do have the strings (core) they are pretty good. It's the only Spitfire product I own. But I probably wont be continuing my orchestral libraries with their products. The Studio series is nicely priced, but seems to be a bit messy with the scripting and issues you mentioned. Symphonic, Chamber libraries do sound quite nice, but they are also out of my preferred budget. I might use the Studio Strings every now and then, will see.