We've just upgraded our 2003 Speedster to Ultegra 10 spd but we went with the Ultegra tandem crankset as well. Dura-Ace chain but only an 11-28 cassette. I'm not super pleased with being locked into Shimano chainrings or with the 30 tooth granny but there aren't a lot of options out there and for our use close to 1:1 is fine. Due to a late spring here in Ottawa it hasn't seen the road yet but we expect to be out this weekend. I'll report back on the shifting with the Ultegra crankset and a narrower range cassette. The old 9 spd moved over to our dirt road tandem which has seen lots of use so I'll be able to provide a "side by side" comparison of the performance.

On the workstand it seems like the new brake levers take up quite a bit more cable so I'm expecting improved braking feel - have you noticed that?