There are some who say that the new version of the lens causes "micro jitters" when recording video handheld, which makes it impossible for use with video. As the lens is advertized for video use especially, this sounds like a very bad thing.
To test if there is merit to the claim, I have tried to put both lenses (the new and old version) on the same camera, Lumix GX7, and recorded video at 1080p, 50FPS. To avoid motion blur, which might hide the micro jitters, I set a fast shutter speed at 1/200s.
Both cameras were connected to a Desmond mini stereo bracket. The new version of the lens to the left.
Here are the results, at 140mm, 50mm, and then 14mm:
Looking at the results, I don't see any adverse jitter effects with any of the lenses. The new lens is not consistently better than the old one in terms of stabilizing the video, but neither does it make the video "useless", as some would say.
Looking back, people would always say that lens based optical image stabilization would be best for video, and, hence, look to Panasonic rather than Olympus within Micro Four Thirds.
However, with the Mark II of the Olympus E-M5, they have taken the in-body image stabilization to a new level when it comes to video stabilization. See my comparison here, which shows a truly amazing performance from Olympus without lens based IS.