Before you go all "vigilante justice" on this add-on, get your facts straight. This is NOT an Amazon product. Your amateur sleuthing revealed an IP address of 126.96.36.199, but that's for Amazon Web Services. Yes, the same arm of Amazon that provides hosting services for sites.
Obviously, the company behind this add-on is hosting their page using this technology, but that's hardly a conflict of interests.
And no, this is not an Amazon product. Double check your facts before your next smear campaign.
Me? I like the add-on quite a bit and find it very useful, but really wish it could show shipping info (like enter your zip and preferred shipment method into the add-on preferences). Other than that, I haven't noticed any issues with the results.