My favourite builds so far have been my Roden Albatros D.Va in 1/72 and my Wingnut Wings Fokker D.VII.
Both are is not without challenges, and can be built either as is, or with detail added which I enjoy doing.
Both have also really benefited from the collective knowledge and assistance of this forum!
I don't really have an S-O-D, but one of my least fun built in a long while has been a non-WWI build: AZ Model's MiG-17. It looks great in the box, but nothing fits, engineering and breakdown is lousy, as is all the missing stuff -the cockpit kind of floats somewhere, as there are no side consoles.
There is also no intake trunking or blanking at all, and that on a nose-intake jet. On top of that it somehow looks wrong in a way, the nose seems too long and the windscreen is off.
I'd say leave that one alone and get the Airfix
Jeroen