The 12-32mm is the best standard kit lens for m4/3. I sold the equally praised 14-42 mk11 for it and they're both very sharp, fast focusing and quiet. The reason I rate it higher is simply down to the size. The only negative being there's no manual focus ring, so you have to use the touch screen to manual focus, but some other older M43 bodies won't allow this feature.
I recently took the GM1 out with my G6, I found the GM1 files easier to work with in Lightroom. The GM1 keeps the noise down when pushing shadows in Lightroom, but more importantly to me they don't affect the colour. With the older 16mp sensor in the G6, if I pushed the shadows up I would find a nasty green tint. The new Sony 16mp sensor in the GM1 doesn't show this at all. I would say there's a stop difference in pulling highlights as well. I never felt negatively about my G6 until I started using the GM1. The single point autofocus is slightly slower than my G6, oddly the continuous focus and lowlight focusing is better on the GM1. The low light performance appears to be slightly better, a much finer grain as oppose to the blotchy look on the older sensors. In the end, I'd say Panasonic have came very close to the nicer files from the Olympus' (E-PM2/E-PL5/E-M1/5/10/etc)
Like yourself, I was tempted with the price drop. I decided to go for it as I sold the kit lens for £130 on eBay (as I already had a 12-32mm) and if I didn't like the body, I wouldn't have lost much selling it on eBay. Over all I'm very impressed, the sensor is quite an upgrade from the older sensors, the size is fantastic - I'm glad to just have a camera I can take everywhere with me.