I want the cMBP but I read that the MBA is better and faster. Which screens are better?
In simple terms, the cMBP has better colors. The MBA has a higher resolution. If you're doing graphics work, the cMBP would be the best bet.
As far as speed, it honestly depend on what you're doing. If your work consists of browsing, listening to music, typing documents, etc., the MBA will be faster due to the SSD. More CPU intensive tasks would be faster on the cMBP. If you add an SSD to the cMBP you get the best of both worlds (though you do loose portability)