I have a great EOS system and I bought a G3 as an adjunct, for when circumstances dictate a smaller, lighter camera. Despite this reason for buying into the M 4/3 world, I am also excited about using my EF lenses and some legacy PK lenses.
I'm also excited about using older MF lenses on my EOS camera. With using one such lens in mind, I splashed out on a 2nd hand Leica R 28 f2.8.
I don't have the Leica-R to EF adapter yet, but I have had a quick play with the G3, really without the full knowledge of getting the manual focus spot on.