I have three - 14-year-old girl, 9-year-old boy/girl twins. If two are together, they play fine. Add the third - and it doesn't matter which one it is - and WWIII breaks out. I love my kids, and if I was asked which one I would give up it would depend on the day and who was behaving the worst, but with regard to the question asked, I would recommend two. There is a reason that all travel packages are set up for "a family of four". And don't even get me started on the cost of educating them...