Nothing really, its the first decent groupset Shimano make and not much different to Sora. For a £300 bike its a cracking groupset!
The main differences between group sets will be weight, durability, crispness/smoothness of shifting and the overall ergonomics of shifting.
As you move up the range these things should improve, but also the price increases.
EDIT: I realise I didn't really answer your question. As Shimmy said, for the price of the Triban that groupset will perform fine and have cheap replacement parts if things go wrong.
ah, awesome! thanks
should be fine for my use! 
does strava show the max/avg speed etc?


I had a 110mm stem on before which gave me a lot of upper back/shoulder pain from reaching too far.