I have to say the replacement lens looks sharper and appears to have better chroma characteristics.
The stock lens has a severe red cast, which mine has and seems to be common to all the videos I've seen. It's quite difficult to correct in post so I'll definitely be looking to get one of these lenses.
My lens seems to work just fine for color accuracy but I've always enjoyed a narrower field of view, I changed all my GoPros to 5.4mm lenses when I was using them with Phantoms. By the way I was happy to see today that Yuneec USA is now using my Iceland footage on their website...