You know Khan has the skills to become a top contender, he has a good jab, he's fast and he has a good amateur background backing him up. He sparred w/Manny Pacquiao to help him on the De La Hoya fight and he has Roach on his side now, if he comes in prepared with a good game plan, I'd say it's a winnable fight for him.
Now let's look at Barrera, he is a veteran of the sport but at the moment were not really sure where he stands especially moving into the lightweight div. and this fight can answer that. He fought a can on his last fight and it was fed to him as a tuneup fight but this coming bout with Khan you can't really count him out because he will definitely be Khan's biggest test, he is still a good boxer with a lot of skills alongside with his extensive experience not to mention he is a good puncher with good power to test Khan's chin once more and that will be the danger he presents to Khan, we all know that Khan got kayoed not too long ago.
This fight is a validation for both, for Khan is he really the prospect we thought he was? Can Barrera still fight? How well can he handle this new weight class? Either way it will be a good fight.