Finally got to drive the new roundabout a couple hours ago and I like it. It seemed intimidating when I was looking at the renderings but when it came to driving it, it felt pretty natural - even in peak traffic.
The old ramps at the 401/3 Y-interchange have been shut down and all connections between 401 and 3 are now using the roundabout. The Hwy 3 flyover is now awaiting demolition (which is this weekend).
From Highway 3 East:
From Highway 3 West:
The approach to the Highway 3 flyover has been walled off:
Sorry about the picture quality - I had to rip them from video. Now that the roundabout's open there's nowhere to take stills.