Size and weight are big decision factors when you are trying to find the ideal camera for your needs.
In this section, we are going to illustrate the Sony TX9 and Panasonic G3 side-by-side from the front, back and top in their relative dimensions. Sony TX9 has external dimensions of 98 x 60 x 18 mm (3.86 x 2.36 x 0.71″) and weighs 149 g (0.33 lb / 5.26 oz) (including batteries). Panasonic G3 has external dimensions of 115 x 84 x 47 mm (4.53 x 3.31 x 1.85″) and weighs 336 g (0.74 lb / 11.85 oz) (including batteries).
Below you can see the front-view size comparison of the Sony TX9 and the Panasonic G3. Sony TX9 is clearly the smaller of the two cameras. Its body is 17mm narrower, 24mm shorter and 29mm thinner than Panasonic G3. As you can tell, actually this is not a fair size comparison since Sony TX9 has a built-in lens but Panasonic G3 doesn't. Once you put a lens on G3, its thickness will increase significantly.
Here is the back view size comparison of the Sony TX9 and Panasonic G3.
Now lets look at the top view comparison of Sony TX9 and Panasonic G3.
Weight is another important factor, especially when deciding on a camera that you want to carry with you all day.
Sony TX9 is significantly lighter (187g ) than the Panasonic G3 which may become a big advantage especially on long walking trips.
Again, this comparison may not be very useful in real life as we are comparing the weight of a camera with a built-in lens to the body-only weight of an interchangeable lens camera. Once you put a lens on G3, the total kit will weigh much higher.
Weather Sealing
Unfortunately neither the Sony Cyber-shot DSC-TX9 nor Panasonic Lumix DMC-G3 provides any type of weather sealing in their bodies, so you have to give extra care especially when you are shooting outdoors. If weather sealing is a must-have feature for you, check these sections: Top Compact Cameras with Weather Sealing Top Mirrorless Cameras with Weather Sealing
LCD Screen Size and Features
Sony TX9's 3.50" LCD screen is slightly larger than Panasonic G3's 3" screen.