I just upgraded to a Panasonic Lumix GX1. The primary motivators for me to get this camera as opposed to staying with the GF3 are the hotshoe for flash, 16 megapixels as opposed to 12 for the GF3 and a socket for a remote trigger / intervalometer.

Pros:​

• ​16 Megapixels
• Remote port for timer / intervalometer. I'm looking forward to making some time lapse videos.
• Improved low light noise at higher ISOs.
• ​Improved Auto Exposure Bracketing (AEB) with the HDR photographer in mind. The camera can go from -2 to + 2 in 5 photos or -3 to +3 in 7. Perfect for HDR.
• Built in accelerometer for a horizon guide. ​
• Cost: $275 on Amazon for a body only kit. As I already have a Micro Four Thirds kit lens, I'd rather save the money for a different lens.​
• More range of light: -5EV to +5.​

​Cons:

• ​As with the GF3, timer and AEB are separate shooting modes.
• Not a big jump from 12MP to 16MP. Tip: ​Crop before you press the shutter button and not in post. Unless necessary.  
• Dial for aperture and shutter speed is a bit firm. I'm used to the smooth wheel of the GF3 to dial exposure and aperture.​ Also this dial is the toggle button for alternating between the 2 modes. I have to check the lcd to be sure which mode I'm dialing.