I just bought the 900 after using the 600 for several years. Honestly, just buy the 600. The 900 has too much power and the base jumps about a bit. I nearly always have a chunk that didn't chop up and I have more trouble with leaking than I ever did with the 600. I winter south and wanted one for north so I didn't have to move it with me. I'm sorry I didn't buy a second 600. Bullet is definitely the way to go and I've recommended it to many people, but I'll tell them to go with the 600.
I have been trying to gain weight to no avail. Purchased some wt gain protein powder and a nutri bullet a month ago. I use it twice a day with milk, protein powder, frozen bananas or strawberries, unsalted sunflower seeds and a couple of ice cubes. It is delicious, takes a second to blend and I have gained 3 lbs!!! LOVE IT.
I have a Ninja & thought it was good. But, I didn't like having a larger item to clean after making a protein drink. So I tried the NutriBullet. Wow. With the Ninja, I would put ground flax seed into my drink and there would always be little particles stuck on the container & would take a long time to get all of it cleaned off, even in the crevices on the lid. No problems whatsoever with NutriBullet. And I don't have to grind the flax seed first, I just put the whole seed in and everything is ground up perfectly!!!
Excellent for smoothies (pretty much all I use it for is frozen berry smoothies) but seems to have a short lifespan on the seal of the blade. This is my second NutriBullet (I exchanged the first one) because the first one seems to leak grease through the bottom of the blade component. It seemed like it just wore the seal or rotor out in less than half a year with weekly usage. I am not brutal on my appliances and I followed directions so as not to overfill the containers but this was disappointing. As for the power of the bullet and the ability of the blades to blend, I have NOTHING but praise to offer.
I am on a weight loss program that involves drinking 2 shakes per day. The shakes consist of a powdered mix, but I add fruit, ice, chia and some other powdered ingredients. I was getting really sick of taking my blender apart to clean it on a daily basis. This thing does an awesome job of blending and is super easy to clean because the blade is in the lid, so you're taking it off to open the container any way. A quick rinse between shakes and I'm ready to go for the second one, then a little soap and water and it's ready to go the next day. I don't use the cup accessories, but my husband does and he likes them... says they stay sealed in his work bag, but de does note that the tries not to turn the bag over!
I tried the NurtiNinja, just to see. Leaked out of both blade bases right out of the box. Took it back and got a nutribullet. So powerful and doesn't leak. Blends everything from spinach to walnuts with no chunks. Love it!