Okay i got this client which would like the 620 option more cause of the captive portal.... but they need to sustein the controller for other reasons not just for that...
A few ideas i got for it, are:
1-With controller you can do remote APS and VIA clients(Not sure if the client need this part i was not presaling this at that time and the guy presaling it didnt mention it.)
2-Captive portal its a way bettter
3-Controller simplifies vlan at edge i do not need to tag the vlans everywhere...
4-instant just can go up to 1024 concurrent users buti dont think they care that... as they are less than 100 users
5-More advanced firewall rules?
6-More advanced IPS IDS Features?
7-More advanced ARM? is the arm with the controller better thant he arm of the instants?? or they are the same?
Any other thing i can say to help the Administrator to go for the controller over the instant aps? which of course is a way cheaper....