Originally Posted by
waterrockets
You won't notice any difference between Ultegra and Tiagra. Maybe after 6 years.
I can tell a difference between my Ultegra and Tiagra bikes. The Tiagra seems a little less smooth in the way the shifter action feels, and the brifters are larger and less rounded. I wouldn't say it's a few hundred dollars' worth of difference on its own, but in my opinion, the difference is apparent.
I haven't tried Dura-Ace, but my gut tells me the difference between that and ultegra is probably less apparent.