Hi Manni!
This is a great question and I'll do my best to answer it thoroughly. We are an Intuit Authorized Hosting Provider.
1. Network Attached Storage (NAS). It's mostly about the compatibility with installing Quickbooks. Most NAS devices are Linux based so the installation of QuickBooks there is not like Windows Server. AND... not in any supportable way by INTUIT Support (they just don't do much of the Linux anymore). The CLIENT part of the application will not work well and there isn't a good way to remote deploy the client without losing substantial functionality. If this is only for disaster recovery and backups, okay. Otherwise, we would not recommend this deployment model.
Versus...
2. Cloud Hosted Setup. A Windows Server Deployment. This is a common and well-supported deployment model for QuickBooks Desktop. This is best for using 3rd party integrations or any web-syncronized apps. Make sure that your Windows Server machine is properly licenced for the number of users you plan on having remote access (RDS).
Our opinion is to stay in a supported platform so that when issues do arise your Intuit Support will be valid.
If you have any questions, let us know.
See you in the clouds.