I much prefer a bucket. That and a foot brace locks me in and makes me one with the canoe.

That said, the seat I used last, solo, was a sliding web. It moved easily when I took the weight off. I wish it would have been placed farther back but the thing I really liked was I could change the angle. My back does not like sitting in a canoe for extended periods of time. One day on a whim, I raised the back of the seat. My back was a LOT happier. It was maybe only a 5° angle and I never tried it the other way because if my back isn't complaining I'm a happy camper.

That canoe was nice because I could paddle on either side as long as I wanted and the seat was high and so I could easily tuck a foot under it and half kneel. That helps keep my knees and back happy too.