Just got $10 off my entire order! I love how Honey just tries different coupon codes and automatically applies the best one. Apparently there's also a point system where you get a gift card after a certain amount of uses/savings you get with Honey (haven't researched yet).
That being said, there are a few glitches that occur with Honey and other sites (like if a site has buy this # of items and get another free item, and a coupon is applied, that free item is often canceled).
That's the only issue, but, honestly, can't be on top of all sites - they all have different standards and models (with good reason, hackers would have a field day if all sites had the same standard).