There isn’t another platform that I’m aware of that offers this level of insight into web browsing behaviours, with the same depth of detail. It provides a staggering amount of information across a wide variety of site metrics—although in some cases it’s quite clearly sampled and then scaled. Review collected by and hosted on G2.com.

The cost can be considerable, especially to access conversion rate data. It's less obvious when it is scaling sampled data and to what degree, so smaller sites can have quite erroneous data. It should be a bit more obvious when it's guessing more than truly knowing so you can make a value judgment not to treat all information equally. Review collected by and hosted on G2.com.