There is an ad-hoc comparison of a few of top existing services here:<p><a href="http:&#x2F;&#x2F;imagga.com&#x2F;blog&#x2F;imagga-and-6-alternative-image-recognition-services&#x2F;" rel="nofollow">http:&#x2F;&#x2F;imagga.com&#x2F;blog&#x2F;imagga-and-6-alternative-image-recogn...</a><p>and here: 
<a href="http:&#x2F;&#x2F;imagga.com&#x2F;blog&#x2F;some-more-image-recognition-tests-some-more-great-results&#x2F;" rel="nofollow">http:&#x2F;&#x2F;imagga.com&#x2F;blog&#x2F;some-more-image-recognition-tests-som...</a><p>Disclaimer: I&#x27;m CEO &amp; CTO of Imagga.