Don't quote me on this and i'm sure someone will clear this up but isn't Double Fish a sister company or possibly owned by DHS? I was under that impression.
If so, I would expect the balls to play pretty similar to the DHS 40+ ABS ball.
I've always been a fan of Double Fish balls in the past. But that was also the celluloid days so that doesn't really mean much now. I'll probably pick up their new 4-+ ABS 3 star balls for my practice at home. When i get around to doing it, i'll share my impressions.
I have bought 2 boxes of 10 Doublefish V40 and they are ok but not better than the DHS D40+. They play like a harder XuShaoFa ball and not all the balls are round out of the box, you may get 30 to 40% eggs. Even though the DF v40 may be cheaper, i would stay with the DHS D40+.