Solid platform -- unlike some other products which occasionally fail to check in, fail to alert, fail to log, Kaseya's core functionality always works.
Remote control, especially in the latest releases, is instant-quick and responsive.
"Emergency" operations, like blocking an executable client-wide, are easy and fast
Other features like patch management, scripting, and monitoring are powerful, despite their quirky UIs.
Important: Kaseya is powerful and complicated. There's plenty of documentation on "how to," but not a lot in the way of best practices or advice for "what to do." Plan on spending a serious amount of time into learning how the product works.
Their development strategy seems to be all over the place. Some older modules haven't seen an update (other than bug fixes) in more than five years, but they're also releasing new modules.
Third-party integrations work well, until they don't. If you build an offering around their managed MalwareBytes integration, you would have been in great shape until 2013 or so, when they stopped upgrading the engine version.