The warmer weather conditions and 13,000 miles under the belt have made a significant difference to fuel consumption. My GT 150 diesel now returns 620 miles on a single tankful, during which it hit a peak of 64.6mpg, averaged high-50's throughout. Never bothered with ECO mode but I do make extensive use of auto stop/start and generally not having a heavy right foot
620mile range is within 10 - 30 miles of my old Mk6 GT 140 diesel but with a fuel tank 5 litres smaller. The tank actually seems even tinier than the old GT as I've never been able to fill much more than 48litres at a time whereas my old Golf would swallow 54litres and that's after running both cars for 5 or 6 miles with the range counter at zero, so it's nearer 6litre less capacity in real world motoring.
Oil consumption is essentially zero after the first service at 9,700miles. The pure white paintwork has been very easy to maintain with standard VW touch-up paint for the inevitable stone chips. A massive difference over the last deep pearl black which was an utter nightmare to conceal chips without looking obvious and crap.
I'm personally delighted with the economy, low insurance cost and 30 quid road tax. So far, no wiper problems, no suspension problems, no leaks, no paint problems and none of horrible rattles/creaks that have plagued a few owners. I think they made a really good effort screwing it together at the Mosel factory.