A good processor is subjective as the processors for the 3 phones are good enough for their own usage, but if you're looking for processor speed between the 3, HTC Desire wins with 1GHz processor compared to 800MHz on Desire-Z and Defy. If you're getting Desire then, I should warn you that the battery doesn't last long. At most, you can get around 1/2 - 3/4 day of usage. Just make sure you bring along your charger with you wherever you go. I don't know about the other phone though.