I guess I'll be the one who admits to using a retractable lead quite often. If I'm going to be someplace where I expect a crowd, or a lot of dogs then I'll use my regular 6' lead, but if I'm going on a hike or away from crowds then I take the 18' retractable. The one that I use is a "tape" style, so it is not the cord and is rated for bigger dogs. I've never had an issue with it, and it actually works better to keep Frankie near me if we encounter off leash dogs on the trail. I can lock it at whatever length I need for passing, or getting around people and then I can let her out to the full 18ft once were clear.
I see nothing wrong with the retractable as long as they're used in a courteous manner. The retractable let both Frankie and I enjoy playing in the rivers, and waterfalls on our last vacation. I don't think I would have enjoyed being out there as much if I only had the shorter lead. I actually enjoy the retractable right now. :) That said, I've never really had an issue with Frankie on one, but I'm sure if I had a bad experience that I'd consider using the 6' lead all the time.