Seeing how much I liked the design and after reading through the overwhelmingly positive reviews, I just went ahead and bought it in three different colours (black, grey and red).
I am usually a size small to medium (in Germany), so I wasn't too concerned with the sweater being one-size. It fits rather well, the sleeves may sit at a slightly awkward length if you have longer arms. My problem however is the excess fabric at the part around my stomach, sometimes there are some weird wrinkles ... though this may just be my fault ^^ (169cm/48kg). So I think that this item fits up at least one size.
It is very comfortable to wear, the fabric is very soft (the grey one even is extremely soft - I don't know why. It may be the chemicals? At first the smell was very unpleasant, but it went away after the first wash).
I had to cut off some lose threads (there actually weren't any threads on the red one) but this was no issue at all.
Sometimes I feel as though either you sweat more or the sweat can't dissolve as easily? But maybe that's just me ^^.
Overall I am very happy with my order, I got many compliments on it :)