There is not a need for any other basis than arna. We talking about a prescription for the worst medical affliction in the world. Exlcluding vvus due to its over priced and safety concerns, and limitations on it avaiability, the only other choices for the next 3 to 5 years are arna and vvus. You know that since vvus got approval, orex is no brainer. So that leaves 2. Do you wonder why pepsi is so big, even though coke is number one. What about McD and wendys, tylenol and advil. Come on, this country does not allow monopolys, and even if so, the people will support 2. This is the easiest choice I have ever seen. So rediculous to think everyone lays over and hands the pot of gold to arna, though that is ok , since i am loaded there. The prudent thing is to spread your money app. 70/30 with arna and orex.Do not expect orex to go below $4.