Canon Speedlite 430EX II and Canon Speedlite 580EX II flashes are the two best flash units Canon created so far. The 430EX II flash is a little brother of the Speedlite 580EX II. It lacks several features but delivers a very good package in a compact body at a lower price. It is significantly smaller and lighter, which can be important to the consumer level users. Also some people are very pleased with having an option of not paying extra for all those fancy features of the Canon 580EX II that they don't need for their applications anyway. But, of course, if you want to get the most powerful flashgun, which is also loaded with everything or almost everything invented so far, then the Canon 580EX II is the way to go.
Here is a list of the main features and qualities Canon 580EX II has and 430EX does not:
If you have any questions or comments, please post them below.