The insurance. It's only $168 for 2 years and there is a 50% chance that you will need the coverage.
Why is there 50% chance you would need coverage?
If you lose the phone 1 time then you would pay 168+100 which is $268 over 2 years. You know you are getting a refurb when you get it replaced so figure the total cost there is 300-400. so your only getting at most $132 in value. If you need a replacement more than a year out, then you can probably get the refurb or used phone for even less online so you aren't even getting the $132 value.
Given that you are more concerned with defects and things covered under the warranty, and do not seem to anticipate loss/theft/unrepairable damage, the AMEX extended warranty would cover you up to $200 in year 2 so you are getting very little value out of it. I don't get warranty coverage anymore, it's not worth it.
FYI, I work with some warranty actuaries and the industry trend will be moving toward $150 deductible for the top line phones (GS4, HTC one, etc.) which will make it even less valuable).