No hiccups so far, they've actually just released an update today, added Firewall, Citrix Remote (better Remote Tool), and a new report as well as PowerShell functionality.
http://www.atera.com/atera-adds-new-game-changing-features/
In total I manage roughly 500 endpoints and about 12 severs in my 9-5, however, I'm using Atera for a handful of personal machines at the moment to roll out my moonlighting gig. Getting a feel for it for a month or two (already went through my trial). I'm waiting on AV to get my boss to sign off.
We are using a complete solution by Atera. This platform includes system monitoring and servicedesk/ticketing and offers several extensions such as online backup and anti-spam. Take a look at http://www.atera.com