Being a network admin, I find it sad that both Apple and Android out of the box can support modern day Cisco IPsec tunnels (which we use today) plus allow 3rd party developers (Cisco, Netmotion Wireless, etc.) to deliver even better clients. Windows RT has missed the boat here. We going to recommend Android tablets over this OS.
Per the link I posted, Windows RT does support Cisco IPsec VPNs out of the box, and per Cisco, at least with the ASA series, it should work with 8.4.5 and 9.0.1 software. I hope to be able to test this soon when our ASA gets update.
The problem is the SSL VPN doesn't work without the third party client which isn't available. And I do agree that Microsoft should have worked with the VPN vendors to have these ready at or shortly after launch.