Own a LCR (210) + have driven a Mk5 GTI.
If you're town-based, TBH the LCR can be a PITA - the low-speed ride is tediously harsh, it crashes into even the shallowest pot-hole etc & the splitter means that most speed bumps are taken at walking pace. However, the LCR feels more stable on motorways & its suspension setup is great on A/B-roads - loadsa grip, excellent for rebound & fairly supple. GTi feels a wee bit softer.
LCR's brakes are stronger & don't forget that the LCR posted a much quicker time than the Mk5 GTI round Top Gear's track.
Autocar's tests have the LCR quicker - eg 0-60 6.5sec (210 LCR) vs 6.7sec (GTI w/ DSG 'box) - but 32mpg touring for LCR compared to Mk5 GTI's 36mpg.
IMHO I'd only forgo a LCR for a Mk5 GTI if latter had DSG, which is fan-bleedin-tastic. EDIT: seems that there're reliability issues with the DSG 'box. For example, a dealer that has a 'Mk5 GTIs wanted' ad on PistonHeads won't take cars with DSGs...