Look and ask here http://www.flyertalk.com/forum/infor...help-here.html Many linked threads in post 3
Several AA refugees (after the ffp changes) looking for better
Several DL looking for better.
What are your common destinations?

AA miles do not expire if you have eligible activity in 18 months.
DL sky pesos not expiring is the exception in the ffp world

The airline you fly most or an airline of the country you live is the best ffp for many people.
The airline you fly and the airline ffp you credit those flights to does not need to be the same.
Freq flyer miles are not equal to earn or burn.

The grass in not always greener on the other side