Just because Juniper's VPN now works doesn't mean Cisco's client can work the same way, or has the same requirements from the OS. This may answer the original poster's question about Juniper, but Cisco VPNs are still waiting...
Actually it does - even if the Juniper support doesn't allow for every security option, it at least allows for the most basic capabilities. Cisco could support this as well.
The important thing is, clearly, the Surface RT is capable of supporting encrypted communication.
That said, Cisco and Microsoft are competitors so there may be some jockeying going on here. Wouldn't be the first time.
It is possible Cisco is saying it is on MS because they don't want to enable a competitor's product. Microsoft could also be blocking Cisco for the same reason, but what is more logical?
Block one of the top two secure remote access providers from implementing VPN, thereby impacting the number of tablets sold
or
Not developing an app for your competitor's tablet to block the tablet from being sold into your client base?
I have no inside knowledge here aside from being in this industry for a LONG time, but with VPNs now clearly supported, the odds are it is Cisco, not Microsoft, that is the blockage here. Unless a Cisco PLM can post details about what they need that MS isn't capable of or giving them... but I haven't seen that since 8.1 SDKs came out.