how does rogue zeus compare cat or atma-sphere?

I would think it would be hard to compare the zeus and cat with the atmasphere amps as it would be transformers vs OTL;which are 2 completely different species of amps with completely different designs.
If you were driving a 16 ohm speaker my money is on ralphs design (atmasphere) and I think it would win hands down over the other 2.
If the speakers impedance curve dips below 4 ohms I would think it would be a very close match with the CAT probally winning; thats my opinion though.
You should compare for yourself and see what happens;probally would be a good learning experience.

If they remain flat at 8 ohms I would consider the atmasphere ma1 mk2.3 or the ma2's (more power) very seriously; it may be worth a call to talk with Ralph from atmasphere; he is a great source of info and won't jam his gear down your throat; as this has been my direct experience.