I just checked http://www.generation-jeans.com reviews and it has some decent score + there were a lot of reviews. I'm guessing it's a French webpage? Can you contact them and ask some questions about those jeans? If they don't respond don't bother.
But I must admit that's freaking inexpensive So I understand your concern.
In my opinion, in general, DSQUARED2 jeans fit much better than Diesel but they are much more expensive. It also depends on the body shape and cut of the jeans. But I think in general DSQUARED2 jeans fit better.
I have 33x32 my regular size but yup 886b stretches quite a bit and I think they fit more loose in the waist comparing to my other thavar jeans. I actually wish they didn't stretch at all.
886b is a really nice wash. I love when sun hits them - they look different than when you are inside.
What I don't like about them is distressed parts. I kinda love it on my 801c but hate it on 886b.