Good relays shouldn't be much different than a good switch. Both have gold plated contacts and the relays have a small wiping action when they close to help keep the contacts clean and of course being sealed keeps the dust away. It's very hard to beat a ladder type setup if you are going with a resistive volume control. Two resistors and the relay contacts in the signal path and constant impedance.
That said, there has to be a fairly long bus for routing the signal to all those relays and the increased surface area may make it more sensitve to picking up AC and causing noise or hum. If they have a ground plane it's probably OK. The price seems very reasonable considering what is provided.
mike
