As the title says, I'm looking for a road bike. Unfortunately I have limited cash to spend and thus would probably need to buy 2nd hand. This does however open up room for a bit more variety. Newer bike with a lower end groupset or older bike with higher end groupset. What I'd like to know is what the big fuss with groupsets are. Could anyone assist. Is there really a massive difference between say an entry level Sora GS vs Tiagra VS 105. I'd mainly be using the bike for commuting, the odd Sunday ride and The Argus although nothing competitive. Just fun. Any help will be appreciated