Aruba Networks is a product that is broadly available and there are many implementation partners available to design and implement the infrastructure for you. Aruba Networks is great if you are looking for a partner that offers a broad range of devices. It can keep a multi-location infrastructure simple once the management interface is set up. Aruba is less appropriate if you want to do a simple setup with a few devices where you want to be up and running quickly. The management interface can be a hassle to set up and if you want Azure integration you are better off contacting an implementation partner that has dealt with this before.
Fortinet itself is a well know name in managing the firewall and security. With FortiExtender they gave an excellent solution for increasing the connectivity within the organization and helps to manage it with the cloud-based system. The implementation helped to achieve lower latency and higher efficiency for the users in the organization.
When there is a problem, the errors provided in the GUI are unhelpful. In order to have a chance of solving most issues I've come across, you need to be comfortable with the CLI.
Most products in the FortiGate product line do not offer POE power support. The Extender requires POE and has no internal battery. This requires a switch or injector between the extender and the firewall. In the event of a power outage, you lose the extender if you don't have it plugged into an adequate battery. As it's installation can be in a different location then the Fortigate, this can be a hassle.
Aruba Networks Wireless WAN stacks really well against its other competitors for its features, ease of implementation, and administration. The pricing is very competitive with great vendor support and excellent documentation. The centralized management feature is really good as it provides a single pane of glass for all administrative items.
Both the Fortinet FortiExtender and the Fortinet FortiGate products are great because they provide the agency with secure technology and allow for good network speed and security. Fortinet FortiExtender and Fortinet FortiGate are both costly and a better lower cost solution would be better suited if the budget restrictions of your agency are very important for you.