I switched from the SLR (the regular 135 gr model) to the Flite carbonio. I was wearing out the leather along the sides of the sadlle every 6 - 8 mos. I would hated having to shell out for a new one so often so I switched to the Flite Carbonio because the shape of the saddle avoids is more rounded off. I would really hate to wear out an SLR carbonio as it gets a really expensive after a while.

As far as comfort the ti rails seem to flex more and result in a more comfortable ride. The carbon rails do make the Flite carbonio a good trade off between comfort/weight/durability.