I've setup VPN for users.

I've NOT installed NPS so must enable each users access via account settings - this suites me as there are only a small number of users who need VPN.

Since I'm about to go live I don't want to mess anything up!
is there any reason why I should install NPS ?

Hi,

Network Policy Server (NPS) provides authentication, authorization, and accounting services for network access servers, such as IEEE 802.1X authenticating switches and wireless access points, virtual private network (VPN) servers, dial-up servers, and computers running Windows Server 2008 with Terminal Services Gateway (TS Gateway).

As you said, there are only a few users; you can deploy your VPN without NPS.

But if the VPN is built in domain, youd better configure a NPS to protect your intranet.

More information about NPS:

Network Policy Server (NPS)

http://technet.microsoft.com/en-us/library/cc735378(v=WS.10).aspx