I think from my understanding your put on metformin if your symptoms are a bit more extreme.I didn't really have that many of the symptoms, like no cysts on my ovaries or anything like hair on my face or chest or acne (although I had put on weight around my middle but not that much)the main thing was I wasn't ovulating.But it may also depend on your doctor and what they want to do.Clomid does have some side effects like for me it was hot flushes and general PMS all the time, ovulation pain etc.I don't really know if metformin has any side effects.