I have a Marconi 2024A that I obtained about 10 years ago. A nice unit that produces a clean signal and by far exceeds its specs. I never had much problems with it. It only failed once. Turned out that a power connector was intermittent. I don't use it too often these days since I have newer generators. The only complaint I have about it is its insane front panel operating concept, but one can get used to that.
I think the main recurring problem is the display, although I never had problems with mine. These generators are well built, mostly from standard parts, and full schematics are available.