The 2013 Sora line is the first to ditch the thumb trigger shifter that it traditionally had, bringing the shifting mechanics in line with the higher end groups which use the 2nd paddle. It also goes from 8 to 9 speed, but still isn't compatible with the 10 speed Tiagra, 105, and Ultegra bits. I had a bike with the old style Sora, and it was functional but I hated the shifters. I'd avoid anything with pre-'13 Sora, and I'm sure you can find a $400 bike in your area that's less than 6 or 7 years old with Tiagra or 105.