Star's can be really reliable or problematic...much like a Ruger Vaquero
The Spanish Illbari police carried Stars for decades...quite reliable.
I carried a Star Model 30 (9mm) for MANY years as my backup duty weapon...in case my issue revolver didn't have enough rounds for the application at hand. Good thing I'm a rather large guy (Bull from Night Court-sized) and can hide mid-size pistols easily. It used to be a challenge to see how many weapons we could hide on our person without being obtrusive.
The only time I ever had any issues with it was when I used the bucket reloads that they gave us to practice with at the range...when using good quality ammo, I had no issues at ALL.
Biggest issue was keeping it in magazines...magazine springs seemed to only last for three-four years before they'd give up...but we're also talking about two thousand rounds a year practice on average.
With a used Star, the main thing is to clean the living daylights out of it as soon as you get it home, make sure the feed ramp has no burrs, grease the rails with a good lithium grease, check/clean the ejector, and use good quality ammo...or high-quality reloads that You Yourself make. Other than that, problems are few & far between after you get it cycling properly.
I DO NOT like Remington basic bulk ammo, but Remington PREMIUM tends to work a lot better.
I don't think I've ever used Winchester 9mm...