DSII bought one for me a few years ago. He uses it for smoothies. I've used it only a couple of times so I'm not much help. It's a Rube Goldberg contraption, too many pieces, too confusing, difficult to clean. I use my ancient Cuisinart food processor or the ancient VitaMix or a stick blender. Once in a coon's age, I'll pull out the vintage Oster. When he moves away from home, I will happily box it up and send it with him.

I have 1 @ work and while it is very powerful and has a larger capacity than most regular blenders, I also find the design less than ideal - esp. the cover, which is hollow and does not seem to come apart for cleaning. Water can get inside when washing it, and then it doesn't dry completely - ew!

My husband just bought a Nutribullet for smoothies since he doesn't like cleaning the Ninja - although it's just the pitcher, blade & lid, the blade is very sharp. I don't really mind cleaning it (I shake the cover once I think it's dry to make sure there are still no water droplets remaining lol). I had an old Oster blender till it died, but it didn't have a food processor attachment. I just find, especially for the food processor, that it blends the stuff in the middle & traps the rest in the 4 corners & even with scraping it down, it just doesn't really seem to get the job done well.