The 5-lug is "better" in a couple of aspects.
1. You get a much wider selection of wheels with the 5-lug pattern. (I think this is probably the number 1 reason most people do it.
2. For higher HP cars you might want them, as they provide more strength and safety.
However there are lots of 4-lug cars out there that get by just fine with no issues.
I will probably consider changing mine over once I get into the 500+ HP range and start launching the car with slicks on it.