I had a old YouTube channel awhile back and i tried this service out. I gained about 2000 subs in just a few days, however i didn't gain views AT ALL... All the subs appeared to be inactive. It's a sub4sub service where you sub to people, gain points and then you use those points to gain more subscribers, kinda like a loop. The way i saw it was that everyone on that site is in for themselves, they don't care about your videos and they care for themselves. They aren't interested in actually watching your content they are just interested in gaining subs them self. Thats why a community like SubXcess fails, because they are all in it for themselves.
I also remember reading an article awhile back saying if you are looking for partnership SubXcess subs don't count.
Anyway thats just my PERSONAL experience from using SubXcess.