Playing from disc myself on Xbox 360 and am surpised but the speedy loading times when entering and exiting from the world map, haven't run into any major bugs (crabs that pass though solid surfaces and a texture pop in I did notice although that's supposed worse atm when installed.)
It takes like 2 seconds from disc to get on the world map from a house, far better then deus ex's 30s + when installed if thats what concerns you more.