Looks like a quality lock. Abus is a good lock manufacturer. The chain could be snapped by some 42" bolt cutters, but probably nothing smaller than that. Reasonable amount of security.
Quote from link:
"CHAIN- This 3/8” square link chain, manufactured in Austria by PEWAG, GMBH is “case-hardened” to resist cutting by 3-foot long bolt cutters, hack saws, reciprocating saws and/or electric grinders."
This is bull. A grinder with a heavy duty wheel will cut through that chain. However, a grinder will cut through any lock on the market, so that doesn't really matter.
The key cylinder appears to be a standard abus pin tumbler. If that is true, one could drill out the cylinder plug fairly easily.
I think, for the money, it is a good lock system. Gotta be heavy though.