Well I own the G9 so I'm probably biased
If you want a camera that has good zoom range then TZ3 is better with 28-280mm. G9 only has 35-210.
G9 wins on image quality, raw, controls, build quality, hot shoe (430EX can make a massive difference to shots in doors.)
have a read of the reviews at dpreview.com G9 one only came out on Friday