I see Ti as the ultimate custom frame in terms of the best balance between ride quality, durability & performance. Sure, a more rider tuned Cf frame can be found but it won't have the resilience to minor/typical impacts that Ti has...Lack of corrosion is another, others have mentioned many of the same reasons already. As others have said, ride and narrow things down to knowing what you're looking for before making a long term investment.

(Gratuitous De Rosa porn...):