I would advise trying both the I-17R and the FX-One before you decide. I have talked to two people who have sailed both and they both said the biggest difference is what happens on the boats when you set down the tiller to put up or take down the spinnaker. The I-17R tracks steadily with slight weather helm prior to putting the spinnaker up and slight lee helm after the spinnaker is up. They both said that they found the FX-One requires control of the tiller at ALL TIMES or it turns radically!