Time will tell....
I did a quick search and one thing I found is pretty interesting. On a direct injection engine, the intake valve never see's any fuel but they do see dirt, combustion vapor(Oil), and oil from the valve guide. The additives in fuel help keep the back of the valve clean in non direct injected engines. This could lead to drivability issues and additional maintenence.
I also noticed that some direct injected CTS engines suffered timing chain problems. The lobe on the camshaft for the high pressure pump will increase the load and frequency on the chain.