When I have done cursory searches, they’ve all been the same. I usually book airfare directly with the airlines and pay with my Platinum card for 5x, but have used Amex, Chase, and Citi to book revenue fares on Delta and Aeromexico with points for the same price as the airline websites. One thing to watch out for is that some portals and OTAs will show the pre-tax price while others show the all-in price, which can often make one look cheaper. If you’re flying economy, you need to watch out for basic economy vs. economy. For premium economy, some OTAs will consider extra legroom seats like Delta Comfort+ to be PE, while others will give you business class fares if there is no true PE offered.
@UpperNwGuy wrote:I won't use any of the travel portals. I don't think they have either good options or good value. My philosophy of credit card travel rewards has been (a) earn the points on Chase or Amex, (b) transfer them to the airline's frequent flyer program, and (c) book my fare through the frequent flyer program.
The downside to that philosophy is that if the value of the award fare is the same or only marginally higher than using those same points to book a revenue fare booked through Amex or Chase, you miss out on redeemable miles and elite-qualifying miles/segments/dollars earned on the flight. If you're doing a transfer for a premium cabin long-haul international flight, then of course in most cases the value of the transfer would far exceed using them in a portal.