In general, the only times I book codeshares to
anywhere are when I can improve earn rates. WS-marketed flights don't earn anything on AAdvantage, but AA-marketed WS-operated flights will earn like AA flights for RDM, EQM and EQP (as
nall points out). Thus, all else being equal, this would satisfy my personal rule and I'd book the codeshare 8 days a week. You would need to decide whether ~3800 AA EQMs are worth $200--they certainly are to me.
Your profile indicates that you're BAEC Silver, but makes no mention of whether you earn AA miles or have AA status. If you're asking from a BAEC perspective, you've posted in the wrong forum.
Originally Posted by
shorthauldad
If I'm arriving in LAS on an AA flight are there any benefits to booking my onward travel via the codeshare e.g. can I check bags straight through to YYZ? ...or does the codeshare not make any difference?
Above you said you need to get from LAS to YYZ, but then you indicate that you're arriving to LAS on AA and looking to get from there to YYZ. Is there a reason you're not just going to book AA to YYZ from wherever you're starting? AA serve YYZ from DFW, LAX and MIA, with seasonal service to ORD...
In any case, if you check in at AA's counters in your city of origin, and you have status that permits free bags on AA, and you're flight onward LAS-YYZ is a connection and not a stopover, you should be able to check those free bags through to YYZ, even on a WS flight. In the reverse, where your first flight ex-YYZ is a WS flight, you'd be subjected to their policies, which differ from AA's.