I have a 4700 Tiagra equipped Roubaix. It is very good. No issues with shifting or anything else. I like the shape of the Tiagra brifters much better than the 5700 105 brifters and the external shifter cable routing is a plus IMHO.

I am guessing the "new" 9 speed Sora is basically the old 9 speed Tiagra. I also have a bike equipped with the 9 speed Tiagra and over 4+ years, I have had no issues with those either.

Looking forward to the 11 speed Tiagra coming out in a few years. By that time, I will be in the market for a new wheelset anyway. I think the 12-30, 11 speed cassette would be really nice.