I have had both the Ti colour and the black ones.
the wheels are very very good and hardly ever go out of true.The surface coating on the hubs and spokes started to 'peal off' of the ti ones. Took them back to LBS shop after 18 months riding they were replaced for a new set of black ones for free.
I live near the sea and Trek say it was the salt in the air/roads that caused this.
The other 'black ones I have had for 2 years with no problems.
So all in all in my experience the tace X lites are very very good.