These days I aim to answer as many queries as I ask as I get better and better with Matrix with the help of others however guess what... I have a question And I hope this helps others too.

On these joint ventures to the USA what is the benefits of booking it on one carriers codes over the other? Ignoring things like what metal you are on because each of the below can book on the others metal

Here are some examples
ALG => LAX
CAI => HNL
OTP => PHX
LAX => PTY

The only benefits I can see of taking a BA over an AA for example is the opportunity to uuA the BA Metal legs to F which for TPs USUALLY isn't beneficial at all and the double avios if booking using the BA Amex ?
Benefits of booking on AA is on bigger runs where more flights are on their metal they are in a much more flexible position to juggle with options as they have access to more inventory and generally more accommodating at the cost of not earning as much avios
Then there is IB which earns practically same avios as BA, Without the extra BA Amex Avios and not heard of how they handle IRROPS.