Hello Gerard28,
I use a Hyberg, not the Attila, but the Aguila (37 litres). I haven't done long trips with this pack yet, mostly day hikes. But for me this model fits perfectly, it's comfortable on my back and I love the shoulder straps, which are really soft. I really appreciated these soft straps last summer in Italy when it was very hot outside and I hiked without shirt for a while (of course not in the sun, haha). As far as the service of Hyberg is concerned, I can say that my experiences with these guys have been very good so far. They run a small UL store in Berlin called Hikerhaus and they are really friendly, also returning or exchanging different gear items never has been a problem.
I wish you nice hikes and that you are happy in the end with the choice of your backpack!
PS: English is not my native language :)