I don't see it either. I am disapointed. In the video link @ 38:02, he said clients would be included in the preview release if they could be fully tested in time. I have to assume that the Juniper client did not meet this criterion.
After installing the 8.1 update on my Surface RT, there were a few more updates available in Windows Update. I hope MS can provide Juniper without making us wait until the full/official release of 8.1.
Do you guys see any Cisco love? I'm traveling soon and this will be a boon for me... only Surface, no laptop.