The difference isn't huge, but given that the G10 is £300 cheaper it scores higher on our performance-per-pound basis - ie its picture quality is up there with the best TVs at the same price level. It can occasionally struggle with very complex patterns, but that's the only minor criticism. Overall it handles HD/Blu-ray content extremely well.
As for the V10, let's get this in perspective. Our criticism of the Blu-ray picture said it was only a "slight" issue, the TV not quite retrieving as much detail as some rival £1500 screens do. Remember, four stars still means "very good, highly recommended". But if you don't need the extra features of the V10, we'd say go for the G10 and save yourself £300.