I strung up a racquet with Gosen Tecflex a few weeks ago and hit with it for several hours. Stringing it was pretty weird -- it seems to just keep stretching forever, even after pre-stretching it. Pulling at 58 pounds, I needed to give it a good 30 seconds on each pull before the stretching would stop. I've never worked with a string this stretchy. But it's limp and smooth, very easy to work with.
On the court, a full bed of it feels pretty soft and seems to have good energy and control. Spin potential felt pretty low. Probably a good option for flat-hitters with elbow or shoulder problems. Like Mikeler, I'd rank it in the middle of the pack on the multis I've used.