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 H300 and Panasonic GX1 side-by-side from the front, back and top in their relative dimensions. Sony H300 has external dimensions of 130 x 95 x 122 mm (5.1 x 3.74 x 4.81″) and weighs 590 g (1.30 lb / 20.81 oz) (including batteries). Panasonic GX1 has external dimensions of 116 x 68 x 39 mm (4.57 x 2.68 x 1.54″) and weighs 318 g (0.70 lb / 11.22 oz) (including batteries).
Below you can see the front-view size comparison of the Sony H300 and the Panasonic GX1. Panasonic GX1 is clearly the smaller of the two cameras. Its body is 14mm narrower, 27mm shorter and 83mm thinner than Sony H300. As you can tell, actually this is not a fair size comparison since Sony H300 has a built-in lens but Panasonic GX1 doesn't. Once you put a lens on GX1, its thickness will increase significantly.
Here is the back view size comparison of the Sony H300 and Panasonic GX1.
Now lets look at the top view comparison of Sony H300 and Panasonic GX1.
Weight is another important factor, especially when deciding on a camera that you want to carry with you all day.
Panasonic GX1 is significantly lighter (272g ) than the Sony H300 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 GX1, the total kit will weigh much higher.
Weather Sealing
Unfortunately neither the Sony Cyber-shot DSC-H300 nor Panasonic Lumix DMC-GX1 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 Bridge Cameras with Weather Sealing Top Mirrorless Cameras with Weather Sealing
LCD Screen Size and Features
Sony H300 and Panasonic GX1's LCD screens have the same diagonal size of 3.00 inches.
Unfortunately, both cameras has fixed screens so they don't tilt or flip in directions.