Ardor and PeerAssets are not really comparable. While both do deliver blockchain-as-service functionality they achieve so using different approach. Ardor is a blockchain network, a NXT 2.0. It is a niche product at best, a solution looking for a problem.
PeerAssets, on the other hand delivers matching functionality but as second-layer service on top of battle-tested Peercoin blockchain (5 years of uninterrupted uptime) and retaining compatibility with existing infrastructure of Bitcoin, Litecoin, Peercoin and other popular coins.
Beside, PeerAssets work on any satoshi-style blockchain network like Bitcoin, Litecoin, Peercoin and others while Ardor is a thing for itself limiting adoption.