Had a 3.0 V6 for 5 years, got 2.2 now.
Performance is better all round with the V6, but I would not disregard the 2.2. The V6 acceleration is obviously quicker, but I find the 2.2 to be more than adequate too, I usually do motorway driving to and from Spain 3-4 times year and its more than capable and it does not feel underpowered in any way like the 2.0.
Fuel economy wise I average 30-31 MPG, not much difference really between any of the Omega engines. But I seem to remember the 3.0/3.2 being slighty better on fuel than the 2.5/2.6.
It's personal preference, the 2.2 gives you average car performance and is more than capable, the V6 is giving you sports performance, It can come down to things such as maintance costs, how easy to do repairs, insurance costs etc etc.
Your always better getting the biggest engine you can afford, or the best deal and there's not much difference in pricing.
