First of all, are you based in the US? (The answers are completely different if you're based somewhere else, because miles/points-earning cards work differently in each country!)
Assuming US:
Originally Posted by
wizesikh
If you guys had a choice, which one would you pick and why? or would you just get both?
Neither. I'd either get the Diners Club charge card (not sure if it's possible to apply for one at this time), or the Starwood (SPG) Amex. Both of those periodically (at least once a year) have offered big (25%, 30%, 50%, whatever) bonuses for transferring points to BA, and somewhat smaller bonuses at other times of year for transferring to DL (AMEX MR has that one too). So you tend to earn more miles in either if you use a card that doesn't earn miles directly, and then transfer. (And, if you can't decide which right now, you can defer the decision until you need to transfer, if you're collecting either Diners Club Club Reward points or Starwood (SPG) points.)
(You may, of cousre, want to get a DL card and/or a BA card
for the signup bonus only, but from the standpoint of continuous use, the Diners Club card or the SPG Amex card would be much better.)