I've found the ride quality of aluminium is not as good as my Ti bike.

Of course, I must qualify this statement as I've only ever ridden an empty aluminium coke can. It's lack of wheels, cranks etc, may have flavoured my rather negative view of the material. I must say though, the fatigue life was exceptionally poor.

Seriously, I have a Litespeed and I love it. Just make sure whatever you get fits.