Both solutions signatures (detection) are ok. G-Data has 2 Engines as users above have mentioned, so:
Detection: G-Data>F-Secure
However in terms of protection, both solutions are questionable.
Performance, if strictly comparing both solutions, then F-Secure>G-Data but as LittleBits said, they do tend to make majority of systems notice the impact on boot/shutdown times as well as CPU/RAM/I/O whilst scan is being done. I wouldn't say they are Bloated but sure could do some rework on some areas.
GUI based, in my opinion, the User Friendliness in terms of GUI and Settings: F-Secure>G-Data
Scan Speed: F-Secure>G-Data
Removal of known infections: F-Secure>G-Data
That should sum up in a nutshell.