I don't know Mirage, (I own Ohm omnis) but a few A'gon posters are enthusiastic about the current discounts on these models from Vanns.com. If the 350 is among these, you might want to e-mail member Johnnyb53 for his thoughts - he's a Mirage guy.
As for omni speakers and rock, I doubt that there's any inherent issue. MBL often demos their omnis with rock because their speakers play LOUD and high SPL rock shows this off nicely. The specific omni characteristics aren't necessarily the primary point there, but, in one track where an electric guitar solo is "hung out in space" in an impressive fashion, the omni dispersion is definitely displayed. I don't know that a ton of rock records allow this kind of trick, but there are certainly a few that do. OTOH, it's probably true that larger ensembles more frequently illustrate this benefits of omnis.
Good Luck
Marty
As for omni speakers and rock, I doubt that there's any inherent issue. MBL often demos their omnis with rock because their speakers play LOUD and high SPL rock shows this off nicely. The specific omni characteristics aren't necessarily the primary point there, but, in one track where an electric guitar solo is "hung out in space" in an impressive fashion, the omni dispersion is definitely displayed. I don't know that a ton of rock records allow this kind of trick, but there are certainly a few that do. OTOH, it's probably true that larger ensembles more frequently illustrate this benefits of omnis.
Good Luck
Marty