They're not exactly the same. Very similar, but the parfum has several small differences. The parfum is very rich, and generally more woody, but it also has a certain fresh floral note (not geranium, either) which is more noticeable. The longevity of the parfum seems much greater - at least for me.
Honestly, you can't go wrong here. A lot of the hardcores here favor the parfum, but if you're more of an EDT type of person, then you might just want to stick with that. Like most parfums, this one tends to be wear close, but wear strong and long.
I like to wear both at the same time!