I have all tiagra components on my road bike, and it works great, shifts fine, nothings broken yet. I bought an entry level because i really wasn't sure how much i'd use it, I still much prefer MTB, but it hurts my knee more, so the road bike gets use when that's acting up. My g/f's road bike had all 105 components and the only thing i really felt much of a difference with was the rear derailleur. Just steer FAR away from their sora crap or whatever it's called. The really base bikes i tried out had that on them and they were really bad. Keep your eyes peeled for used bikes, I bought mine on ebay and it only had like 150 miles on it.