My preview from http://www.punchdrunkgamer.com/ you can also read what a whole bunch of other fighters think as well...
My gut says Lesnar, but my head says Couture.
Elvis Sinosic – “This is one of those matches that has everyone swaying left and right. In theory, Brock Lesnar should not have the experience nor the cross training to be in a HW title shot against someone as decorated as Randy Couture. Lesnar has not faced the number or the quality of opponents that Couture has. Let’s ignore that he may not have earned a title shot and have a look at the merits of this mach. The thing is that Brock brings in a comprehensive freestyle amateur wrestling background. He also brings in the physical tools of massive size with strength and the explosiveness rarely seen in the HW division. For his cons, his chin has not truly been tested and his ability to push the pace for 5 rounds and come out strong on the other end. Randy brings a great amateur Greco background. He brings in a ton of experience not only in MMA but also in Title shots. Randy has the endurance to push the pace for 5 rounds and come out strong at the end. Some of Randy’s biggest losses have come to bigger guys that can put him on his back. It should also be noted that Randy’s losses to the bigger guys was also when he played a more Jiu Jitsu game plan when put on his back. Since then he has evolved his MMA to better reflect his wrestling background. His goal now is always to end up on top. The big questions are who will put who on their back. When it happens can they keep the other on their back? Both will be playing a wrestling MMA game and I doubt either will try and play guard. Next, is can Brock take punishment, e.g. how will he fair when his chin is tested? Will Randy be able to test that chin? How will Brock fare in the later rounds if the fight gets there? How will Randy’s endurance fair when carrying the weight of a heavier opponent as they can do as much damage to your cardio as can getting hit.
We know that Randy has a good chin. He won’t play guard and will no doubt use a wrestling style game (similar to Heath) if he ends up on the bottom. I don’t see Brock stopping Randy early and I don’t see him subbing Randy (unless Randy is already hurt). I don’t think Randy will sub Brock either. I don’t see him stopping Brock early in the game either. Randy hits hard and has fierce GNP, but has never had that one shot power to end the match. I think Brock does, but I don’t think he will land that shot early as I’m sure now everyone will be expecting it. This fight will be decided later on in the rounds and most likely go to Decision. The question is who will be able to impose their will during the match. I think Brock will come out strong early and most likely take the first 2 rounds. I see Randy rallying back later in the fight (not unlike his match against Rizzo) and taking rounds 4 and 5. The question is who will take round 3, which I think will be the pivotal round. I think the match could also be ended in the third, but most likely both fighters will fight out of it and survive. Whoever wins the third will win the fight. I think Randy will come out on top in the third and use the momentum to drive forward to a unanimous decision victory.”
As you can see, I've gone with my head...
Elvis