We went from a q100 to a q220..
We are a family of 5 (2 teenage boys) and find the q220 big enough.. We sometimes have extended family ( another 7) and still found the q220 ok, but had to cook a couple of waves.. For xmas, we had a 4 kg turkey, and it roasted nicely in the q..
The only time I wish it was bigger is when we do pizza.. It would be good to put 2 pizza stones at once...
I think someone on this forum has an answer for that too..
Ras