As with all exhausts, the difference is mainly decorative.
As for longevity, I'd choose the titanium unit.
The reason is that, while I have carbon-fiber mufflers (and they looked real good when new), their appearance degrades over time with sun, ozone, and heat.
Some have higher quality epoxy in the matrix that maintains it's appearance longer.
I have seen degradation in appearance in mine in just one year of daily use.
Most manufacturers have repair kits that replace the outer skins due to damage, etc.
I plan to replace mine with titanium next time.
The weight difference is minimal. The outer skin is not very thick.
As for sound, the Sato's sound fantastic. Deep and throaty.