I find that the road map and RND were fantastic and that Kaseya is always improving their application for better workflows and productivity.
The integrations are powerful and will hopefully provide a strong value case in time savings as we move down the road using it.
We use the VSA and BMS, hosted version of Kaseya, and the ability to access it anywhere is great, it's easy to gain remote access and set control.
Billing is a terrible, horrible, no good feature. You have to approve billing items, then create invoices, then go into each invoice and choose an invoice "template", then send them out to clients.
Converting from Autotask to BMS was a little bit of a challenge. We have a lot of integrations and it made the project management of our implementation difficult.
Lack of some essential functionality that many bigger MSPs may need.