You can transfer UR points out to multiple travel partners, so they are definitely more flexible. (johnnyjet.com)
If you want to be able to transfer points: Chase Sapphire Preferred: This is a popular card for travelers because of its ability to transfer points to multiple travel partners (including United and Southwest). (creditdonkey.com)
The card earns Membership Rewards points, which can be transferred to multiple travel partners or redeemed for airfare through American Express Travel. (rewardexpert.com)