athier wrote

MSo, why should I choose the Option with the HW Controller?

If this question arises for you, you shouldn't choose the HW controller. :D

Seriously, see the data sheet and the manual of AC50/500 and compare with the data sheet and manual of EAP Controller. If you need functions the HW controller offers, use it. If not, consider use of the EAP Controller. Main difference is the level of configuration options the HW controller offers compared to EAP Controller. AC50/500 is suitable for big enterprises with an own IT department and requirements for high WiFi availability and fail-over for example, while EAP Controller might be better suited to small and medium businesses, who prefer a more easy-to-use WiFi network.