No, it won't do autofocus on a newer Canon or Nikon lens, but Sony makes quite a few auto-focus lenses for this camera under the Zeiss moniker.
The VG900 comes with a LA-EA3 adapter that will allow you to use Sony Alpha lenses. I'm not sure about being able to auto-focus with this adapter - google it, cause I don't do auto-focus, sorry.
This first impressions video is mostly about controls, and how the camera performs in low light. Watch the video and see some sample footage, make sure to select HD for best viewing:
I was impressed with low-light performance, my wife shoots with a large pro camcorder costing well over $10,000 and as most news photographers will tell you - shooting at 12db the image looks extremely grainy and noisy, ask my good friend Alex Pimentel, he's been a news photog for many years. Alex saw the footage I shot with 21db gain and was blown away.
Update: as of October 2014 - this is still the only interchangeable lens, full frame video camcorder available with a "video form factor" Sony always amazes me, not necessarily in a good way - this time they did.
WIKI List of large sensor interchangeable-lens video cameras