Quick question:

I have a few miles on my United and the same on an AA account, and no status, but hopefully I'll be able to fly more in the near future. I want to stick to one airline, and I'd like to consider the differences between those two. So my question is, is there an "AA or UA" thread or a page to compare these two airlines, for example fees, mileage programs, entertainment, meals, etc.
A comparison chart of these two airlines is available?. I did a search, couldn't find the American or United thread. My routes are EZE-YVR, YVR-LAX or YVR-JFK, and probably and I wish one roundtrip LAX (or YVR) - MEL.

Many thanks in advance.