I tried it for about 8 months. There was some growth, but I never got any tissue formation or budding. It did move some fat around for me, so there was some benefit. It was expensive, and I went through it very fast at the recommended dosage for men.
PM ended up being cheaper. If you look at Nature Days ingredients you'll find most are available at health food or supplement stores. Some of them are worth adding to a PM based program, others don't have any benefit.
My opinion is that the active ingredient is Fenugreek, which is available everywhere.
PM+FG did more for me in 3 months than ND ever did, and its still working.
On the other hand, I think Sexless6969 reports some excellent progress on ND - at least the pics look pretty awesome.
-j