Go for iPhone 6. If you are a simple user then you won't get to know the difference between the processors and chip. If you are a tech geek like me then go for iPhone se as you will feel the speed of iPhone 6 is a bit slow than the se and their is a difference in gaming. If you need a big screen go for the iPhone 6 but if you need small go for iPhone 5s not se. Don't think that se came after 6 so se would be better. This isn't so. iPhone she is the successor of iPhone 5s. Now iPhone 7 is also realised which is the official successor of the iPhone 6 and iPhone 6s. I would recommend you 6 iAd it much more lighter than se but she gives the premium look of iPhone 5s sonnormal users won't even know whether its se or 5s. So either go for 6 or 5s.
As such both have its own importance like size and feature. As iphone se is smaller in size so if you dont want to buy big screen phone it is best.