I think that when people say that the X-box has better graphics, they are very poorly informed. When I got my PS3, I compared it with the X-box 360 to be sure I was making the right decision, and I can tell you, the Graphics look the same. And too say that the X-box is aimed at Mature Players, it really a load of Horse crap.
Both of the systems come with games that are similar and the online is great. If you going to look for what really suits your style, pick a couple of games that you know you will like, and buy the system they come for.