I just made the move from Al to Ti. I don't notice a difference in ride quality when I'm in the city. I notice a big difference when I'm out in the county on the chip sealed roads that haven't been maintained for years.
I only have ~200 miles on the Ti with a longest ride of ~50 miles. I'll probably put 80 miles in this week end. At that distance I can feel a difference in overall fatigue after the ride. I'm not talking about just being tired from the ride, but my joints don't ache and I'm more willing to get back on the bike the day after a long ride.
Is it the Ti? Is it the new bike smell? Only time will tell.