L579 is a good gun. Tons of them floating around the second hand market here.
The only thing to really look out for is the rifling on the barrel. They made micro rifled barrels for a short while with 12r in them, and those are the barrels you don't necessarily want to own. They get shout out fast, but luckily that manufacturing method is pretty rare on L579 and easily checked for visually.
Clean the trigger and the firing pin thoroughly, and you'll have a great and reliable gun for years to come. If one of these come in for repair its basically always just a matter of cleaning, or if the gun is shot with a ton maybe the odd extractor spring swap, but thats about it. Very robust, all metal construction is pretty much fool proof.