A lot of people have described the TI JF344 set as "flapping in the breeze." I've never gotten that. Having said that, the La Bella Low Tension flats are comparable - I think the main differentiation is that the wraps on the TIs are a little further spaced, making them more flexible. The LTFs (originally called Flexible Flats) are just a smidge less flexible. The 760FL set (43's) are a smidge tighter, and the
760FM (45's) just a smidge above that.
To be honest, the 1954 set ("bridge cables" aka the Jameson set) is heavy, but still doesn't seem to have as much resistance to me as a set of Chromes or Rotosounds. I can tell by how much knuckle pain I have after a set.
I think the main difference between the TI JF344's and the 760FL set is in the tone. The TI's will have more mids, and the La Bella has more low end thump. Both are excellent and I'd have trouble picking a favorite - kinda like a great hot sauce.