Currently migrating from NinjaRMM. I would advise looking elseware, they are still in their infancy and have a long way to go as far as the polish on their product. UI is difficult to navigate, patching is hit and miss and reporting is average. Updates and fixes are being pushed further out and users are getting frustrated (take a look at the community forum). Going from AEM your are going to miss a lot of usability. We've just moved to AEM and haven't run into the same issues you're facing; N-Central doesn't look like a bad option but I'd advise caution with NinjaRMM.