Here is my 2 cents.
I have often thought of leaving for greener pastures, however after doing the research this is my conclusion.
Most of the so called best airlines are small and have a small number of flights compared to United. (it is easier to please a smaller group of people
)
I also noticed that if you build yourself a pros and cons list you will find that if you want to be able to travel all over the place United is the right choice.
Pros
Star Alliance
They cover a lot of the globe.
They offer Clubs
They offer great deals (not all the time)
I traveled on about 82 flights last year and they only lost my luggage once and it was delivered to my hotel later that night. Yes there are problems but in the grand scheme of thing the good out weights the bad.
CT