well in EU the omega is very cheap to maintain (except fuel consumption in v6) yall got 3.0 v6 in the catera but in the EU we have 2.5 and 2.6 as well so they are slightly better on mpg. when it comes to maintnance like i said the omega is cheaper to buy parts etc than the 124 but that could be a whole different story in the US you know, the omega is for sure less reliable than the diesel MB, but imo the omega (or prefacelift catera) is much cooler and better looking midsize sedan