I've done a full cycle of Nzero and it's the best preworkout for crash-free pump and focus. It's just too expensive for me. Quality of Cellucore's stuff is great, but you pay for it. It's best getting it off of ebay.
I wish I could give you my own opinion but there is no damn way I'm spending that kind of money when there is so many other good products out. But...a guy I work with was bragging about the gains he made while on a product made by Cellucor and said it was one of the best product out there. And keep in mind, this was after he took Winstrol. So to me...if you have the money then give it a try and let us know BUT there are plenty other good products out there with a lot of reviews and only a percent of the cost. Just my $.02 though. Let us know what you decide though, I'm definitely interested in hearing about someone on AM using Cellucor