In general, this add-on is decent, but I've had three big issues with it.
1, It's dumb. There has been an occasion where I had manually applied a code and by running Capital One shopping it actually removed my (better) code, and applied one that gave me less savings. Irritating to say the least.
2, The second issue I have encountered is it doesn't seem to be able to apply more than one code even if the codes can work together.
3, It's inconsistent. I removed a code, messed around in the cart, ended up with the same stuff, came back. When Capital One ran again, it gave me a code that had didn't save as much. Why didn't it apply one of the better codes? This is also how I found out about multiple codes, because I added the first one back (I don't trust C1 shopping so I saved the code) and managed to save the most with the combo of codes.

It has definitely located better codes to save more money with minimal effort from me but this is not a perfect solution, at least on the coupon and discount code front. Still easier than me searching them up, though!

breaks the domino's website. automatically starts applying coupons slowing everything down. and gets rid of special offers like $2.99 bread bites and instead charges 4.99.

The rewards are nice, and occasionally it finds a better price at another site when I am shopping on Amazon, but I am beginning to seriously dislike the automatic application of coupons on some sites. On more than one occasion, it has replaced a coupon code that I had entered with another code that was not as good and made it difficult to use the code I wanted. It would be much better if the codes could be offered to the user without automatically applying them.

How do find my orders? I need to return one?

Not sure about this site. I tried once and, yes, a lower price was indicated. BUT I would have had to pay full price and get some kind of coupon to use for something I didn't care for. I'm sorry I'm so vague, but it was several years ago and my brain is tired and retired.

So far, OK, but not always sure when it is working!

Haven't found many discounted items through the Amazon site

Don't seem to get alternative sources; just 'discount' codes that rarely work.

It is great when it works