I presume we're talking Disco 2, like the one in the photograph.
I already have both several Omegas and a Disco - the general concensus is right, it's horses for courses.
the Disco is great for generally woofling about the place and towing stuff. It's actually quite fast, but that's not the point. Its easily fixable when it goes wrong, mind you Omegas are as well. And of course you can drive up the side of a building in it.
Regarding the Omegas, I have five, so it's a bit difficult to choose a typical one. But generally, they're proper grown-up saloon cars, the thinking-man's BMW. Quiet, refined, reasonably economical - all of which the Disco ain't.
so its up to you to think why you'd want a vehicle and select the best for your needs.
I would definitely say that the Omegas are all much, much better over potholes than the Disco - and we live on a farm in rural Northumberland.