I have a CDI furler, and it works ok, but raising the sail is hard. A few tips:
1) when lowering the jib, make sure you first have a strong messenger line tied to the metal slug that is pinned about 2 feet from the bottom of the furler. As the sail comes down, that slug will slide up the furler foil. To get the sail back up, you will need to pull hard on the messenger line.
2) be careful when unpinning the slug. Mine had a cotter pin through the furler foil and the slug. The first time I took the sail down, I got some pliers on the cotter pin and yanked it out...the slug was pulled up up the furler foil (it is under some tension), and caught me close to my eye. Luckily, I had sunglasses on that took the brunt of the hit.
3) When raising the sail, use soap or sail-coat on the rope bolt as you are threading the sail into the foil slot. Also, put some lubricant on the metal slug as it will ride in the foil slot and easily binds.
4) when putting the sail up, thread the messenger line through the sheave just above the furler drum, and then pull up on the messenger line. This keeps the pull on the slug straight in line with the foil track. Pulling down on the messenger line any where but straight in-line with the foil track makes the job almost impossible...don’t ask me how I know.
I like the CDI, since I don’t change the jib during the season. Getting it up can be difficult (but tip #4 is a big help). Once up, it works fine. Pulling the sail down is not difficult.
Greg