Universal was one of the early, original post-war carbine "clones".
The earlier models were made up with new cast steel receivers, and all USGI parts.
As time passed and the supply of GI carbine parts began to dry up, Universal began to make new parts from castings.
These guns were interchangeable with GI carbines, and quality was fairly good.
At some point, Universal did a complete redesign of their carbine and it became more of a carbine "look-alike".
They completely changed the gas system assembly, and changed to an odd-ball double recoil spring assembly. The operating rod was changed to a design which had an open cam surface for the bolt lug, instead of the enclosed surface used on the GI and earlier Universal guns.
It was these modified "look-alike" carbines that got a reputation for quality and reliability problems. In short, some seem to run fine, other give problems, with no real way to tell which is which without actually shooting them.
Sometime in the 80's, Universal went bust, and was sold to Iver Johnson, who made the older-style GI-type carbine. IJ's quality also varied, and their carbines also had a rep for problems, until they too folded.
The bottom line is: If your Universal shoots Ok, good. If it won't, don't spend any money on it, you'll probably be better off to get rid of it.