It depends on what you are looking to get out of it. The galaxy is mainly for web browsing and gaming, while the iPhone is actually a phone. So if you already have a cell phone, I would suggest the galaxy, but if you are looking for the Swiss army knife of phones, them go for the iPhone.
I believe this is determined by personal taste of the phone as well as the features one needs in a phone. What is best for you will not be best for the other person. Personally, I have an iPhone and I like it.