This tool is very reliable in terms of tracking website traffic for different websites across multiple domains or subdomains using Google Analytics 360 as their backend analytics solution provider (it supports GA 3rd party cookie).
The UI could be improved upon but I do not find that too distracting from how good this product actually works! It's one thing if you cannot get it working properly; however, when something does work right out of box - there really isn't much else required than just plugging things into place without having any issues whatsoever. We have been able monitor user behavior/traffic patterns through various sites hosted by us including internal ones which we use internally only within our organization itself such as intranet pages etc., external facing landing page optimization campaigns where visitors are directed towards certain webpages via link clicks or direct visits to those particular urls.