I was at the park yesterday with my family, and took 2 rides on WindSeeker; one in the late afternoon, and one at close.
I don't care for heights, and this is the most apprehensive I've been about getting on a ride in a long time. The line did spill out into a temporary queue that runs along the front fence of the ride, which was about 30 minutes. An actual full queue would be about 20 minutes.
The sound system was set to the same music as is already playing in the speakers around the park (general comment on that - too loud!). This makes sense because there are so many speakers in the ride area anyway, that if they tried to play something different (like at CP with their sound track), it would clash with the fixed speakers on the ground. So it works well.
Of course it's very smooth, and very quiet. I didn't notice any substantial relative motion between the seats at all. Certainly nothing like we've seen in the footage from at Cedar Point. I wonder why their ride seems to have so much more of an issue with it than we do up here?
Overall it's really pretty. I don't think I'd ride it by myself, as I'd still have to have a riding partner to convince me to go on it.
I think it's a fantastic addition to the park, and based on the demographic of people riding (everyone of all ages), they nailed it. Right on, Wonderland and Mondial!
PS - Yesterday was a perfect day to visit, the weather was great, crowds were light and almost everything was a minimal wait or a walk-on!