Not to get gritty witty about it, but you're oversimplifying a huge field with lots of problems. Are your cabs phase aligned with the speakers of the PA? No they never are and never will be and it does not matter at all.I just thought of a good reason to use this over the Torpedo CAB...
Digital modellers introduce a small time delay due to the processing involved. If you have an on-stage rig and are just using the cab sim to go to the PA, if there is a time delay between the signals you will get nasty comb filtering effects (kinda like a frozen flanger). An analog filter won't have this problem!
Yes, digital effects have a latency. But so does sound when travelling through space.
I think the biggest advantage of the Omni is the limited set of controls (in comparison to digital devices), it's instant tweakability and (if yes) the good sound. Does a cabsim need to have more controls than that? I don't think so. I like analog pedals that provide me with what I need.
