My first modern-day road bike, which I still ride, came equipped with a Sora triple 8-speed and thumb shifters. After a little over 26,100 miles, it's running just fine, and contrary to popular belief, it stays adjusted quite well.

My "good" bike, a carbon-fiber model, is equipped with Tiagra triple 10-speed. With a little over 13,700 miles on the Tiagra, it too is running just fine and stays in adjustment. The Sora and Tiagra have outlasted the 105 that I had on an earlier bike.