Pretty much sums it up the main difference at this price point will be the shifters and mechs .
Sora = thumb shifter +brake lever which some find hard ( ihave sora on the commuter and it works fine the only ting is to up chnage on the drops you need to move your hand and how often will yu be on the drops ?
tiagra = lever under brake lever + brake lever so you can reach it from hoods + drops
sram = one lever under the brake lever that does both up and down shifts depending how far you push the lever .
microshift= seperate levers for up + downshift, not many people use this but they work and are cheaper than most systems.
EDIT forgot campag, but not many bikes at this price point have them.
Having tried all of these they all work but some people like one or the other