These days, there are many credit cards that offer the ability to book any travel item you want through an online travel portal with no black out dates. Therefore, let's see how Discover Miles stacks up against it's peers.
Blue Sky from American Express® - Both of these cards are very similar. But the Blue Sky gives slightly more value for their points. For Discover Miles (and most other card), 10,000 points gets you $100 in travel value. For Amex Blue Sky, you only need 7,500 points to get you $100 in reward value. That means that rather than getting 1% in return, you get 1.33% with Amex. In this aspect, Amex has the slight edge.
But Discover has a couple of features going for it. Firstly, there is no foreign transaction fee. Secondly, for flight accident insurance, Blue Sky requires you to enroll in their service and if you do book an airline ticket, there is actually a 4.95 charge per person per trip for travel accident insurance. Discover provides this service for free.
In these aspects, they come out ahead.
Chase Sapphire(SM) Card - The Chase Sapphire Card is Chase's no annual fee reward credit card. Like the Miles Card, you earn one point for every dollar that you spend on the card. BUt you get to earn double points if you book an airfare through Chase Ultimate Rewards travel portal. Like this card, $1,000 points gets you $10 in value. These two cards are really nearly identical. The differences would be in the little details of their reward programs and online shopping portals. The advantage Chase is that you can earn double points for travel and restaurants with no annual spending cap whereas there is a $3,000 annual spend limit on these two categories. Chase also gives you the option to use their travel portal if you wish to do so.
But this card does not have any foreign transaction fee and that is an edge they have for folks who travel abroad.
Citi ThankYou Preferred Card - The Citi ThankYou Preferred Card is the no annual fee reward card of Citi. The reward formula is the same (ie one point per dollar). The value of the rewards is also the same (ie 1,000 points is worth $10 in travel value). But this card does allow you to earn double points on travel and dining for up to $3,000 in annual spending (which Citi does not have). Citi's card also has FX transaction fee.
But the biggest difference is that to book your travel, you have to use Citi's online booking portal. Therefore, you do not have any flexibility to use your own agents or get the best deal for yourself.