That it is easy to use and you can always see your progress what lets you know if you worked correctly and if your rating already improves. Also the SEO function is very good.
Easy to use, great product, provides functions that we really need. Though we've only been using it for a short time we really like it and have already improved our website quite a bit as a result.
Siteimprove makes it ease to optimize our website, giving quality scores and making it easy to identify where we can improve the SEO and overall user experience.
I got my site from being pretty bad on accessibility to being way above the industry benchmark.
However, for an enterprise, if you're not willing to spend some money to keep your sites accurate without a lot of person-hours, you're probably doing it wrong.
When I used it, I noticed a lot of false flags - it would say a link was broken when it really wasn't. It's also an expensive software.