I got one in April. Really pleased with the fit and function of the back. Been very good in wet weather and the 'buddy pocket' on the lid is quite helpful.
However, I do have a few gripes.The clips on the hip belts are a little flimsy. If you don't loosen the tension on the strap before unclipping you will snap the side of the insert clip. To be fair, when I raised this with Montane they were very understanding and sent a replacement out in the post straight away with no questions and at no cost.
Secondly, after a weekend in the Lakes I noticed where the straps had torn (maybe about 0.25cm?) where they join to the top of the pack. Maybe this is the result of swinging the pack on to my back when fully laiden, rather than more carefully placing it. Maybe, given that it seems to be directed as a 'fast and light' type bag, its just that you need to handle with more care. I've not experienced this with my old Berghaus pack, but then that was half as heavy again.
So - in short, very good, functional pack. Long term robustness yet to be seen.