I have always worn the traditional dark Sperry topsiders for sailing, until I read this thread I really had never considered any alternatives.
That being said, I have always found them to perform very well. I have worn them for several weeks at a time and always find them comfortable.
This is probably already known to you, but I would recommend having a second pair for off the boat and keeping a dedicated pair to wear on the boat. The soles are very grippy and will easily pick up small bits of grit when worn in port, which if not changed out of have a large potential to scratch the boat decks and woodwork. If you are sailing on another's boat they will love you forever*, for having the courtesy to remove your street shoes before boarding.
alaric
*This is not an exaggeration. When I was a freshman in college, I went on an interview about crewing on a boat in the Med for the summer. Naturally, I went to the interview wearing a nice suit and a pair of Aldens. We sat in the marina restaurant for about 20 minutes, discussing my (lack of) qualifications. Then he asked if I'd like to see the boat, which was a "yes" of course. When we got to the end of the dock, I removed my shoes and socks and hopped over the gunwale and got a great tour of the 64' Little Harbor. I found out latter that I was chosen over about 20 other applicants solely because I took my shoes off. I was told all aspects of sailing can be taught, but consideration seems to spring internally. It was a great summer. I highly recommend to anyone with the slightest inclination to the life aquatic, to try crewing. It can be great.
-a-