Hi Coco
I think it's a little heavy and under-specced for 600 quid. Something off-putting about GT roadbikes (at least for me), that I can't put my finger on.
You could definitely get a SORA equipped bike (1 groupset up from 2300), with 18 gears, as opposed to 16 on this. Folk will doubtless be along to give specifics soon enough... if you are not fussed about the brand and are able or willing to get it checked over after collection, have you considered a
Carerra Vanquish? A lot of bike for 600 and Tiagra too. EDIT: just checked and they are 500 at the mo!
I'll be back later with more ideas - you have made me go and look at bikes on the interwebs now! Shame on you
SD