upgrading to digital RAS

I have a dozen analog modems connected to NT RAS. I have as many as 200 mobile users. Some of them connect from remote locations without access to metropolitian ISP’s. I’ve been tasked with upgrading to digital RAS on ISDN PRI.

I’ve started tocollect information on Cisco’s 3620, Equinox’s Digital Modem Pool, 3com’s SuperStack II RAS 1500, Brooktrout’s PCI PRI ISDN card. Does anyone have experience with any of these products? What are some of the typical pitfalls in setting up such a system?

I’d like to encourage more VPN usage, but I have to do this right now… plus, I could make that topic into another question.

Thanks for your help,
tim