Purist Audio Design in One word

I used to own Musaeus range, which is a very good performer at reasonable price when compared to upper models. 

Never heard Musaeus, should be good, at least newer revisions.
Don't buy Maximus - it has low resolution and is too forward sounding. I think, the best value is Colossus fluid, any revision beginning with the original. Very difficult to find. Don't buy Colossus Ferox. This cable was designed with fluid, Jim Aud of Purist just stopped refilling it with fluid at some point. With Ferox the cable is off the balance. Now, if you buy fluid Colossus you will be unable to have it refilled so it's a risk. I had my Colossus refilled once seven years ago - it is still full. I heard that Purist improved their sealing technique and newer and newerly refilled cables may never need a refill. If I ever replace Colossus fluid I would have to go very high in Purist line, to Neptune.

How do Purist cables diff or similar to Cardas?

How do Purist cables diff or similar to Cardas?

I much prefer the Purist. Both can be pricey. Musaeus is a very good entry level cable. We've been using Neptune at recent audio shows with excellent results.