I need 200k on AA to reach 1 million miles and wanted to reach this level by converting miles. The only program I am familiar with is Hilton HHonors.

Under Hilton, my plan would be to transfer 380k from Continental for 760k HHonors points which would then translate into about 190k AA miles.

Can I transfer them through American Express Membership Rewards, Starwood Points or Marriott Rewards with a better rate?

It is a shame to basically waste 50% value of the miles.