In this case I think BA is better, for the bonus and they dont charge the .06 transfer fee on BA points like they do on CO....sounds like you have enough spend to still get CO topped off after the BA bonus disappears. With MR points, always go with the best bonus, if you can make use of the program.
I too have noticed how much crappier UA is compared to CO in availability of awards...I am trying to figure out how much I need to cap off FF accounts at even numbers for expected award flights...like BA 100k will get me 1 first class on AA@75k to Hawaii and a 25k AA lower 48 award. any extra points in BA program would probably be wasted.
Since AA now charges fuel surcharges to Europe like BA does, I may just save their points for hotels and car rentals.
Combined UA/CO points are around 128k for me and 101k for the wife, so we will top hers off to get enough for Europe, up front, and hope the new UA system after the merge has better availability.
DL points are the most active for us, since we are in ATL and have many choices. we have enough for Europe, as well as the many non-stops available to the Carribbean. We dont think much about topping points off for the future, since we use DL the most.
I like the options for cash and points that make use of leftover amounts and the programs that allow OW bookings.
We are closing our MR gold cards instead of paying the $175 fee and using the DL Amex instead...for the same annual fee (or less) we get MQM bonuses, free bags, and pay with miles options. More useful perks (to us)than the MR cards.
MR's best perk was versatility in points exchange, Cap1 beats MR for travel redemptions and versatility, so with all the Cap1 points we have, MR isn't needed anymore.