I had recently owned a Nutri Bullet 600w, it wasn't all that bad, but the seal around the blade kept coming off, as well as the seal around the lids. It didn't chop ice that well, and it still left little chunks here and there, so the consistency was poor.
The Nutri Ninja Pro beats the Nutri Bullet 600w hands down, the consistency was great, and smoothies tasted like something I had bought from Smoothie King. I made margaritas last night, and they were like restaurant quality!
I would definitely recommend this blender to anyone who is a health nut, or just likes great frozen drinks in general. The only thing this blender cannot seem to crush up is berry seeds, but I think they are so small that pretty much any blender won't be able to crush them. I did notice less berry seed content compared to the Nutri Bullet 600w, so it's still a winner in my book.