There are now numerous companies making them, but the two most popular brands are Blendtec and Vitamix.
About 6 years ago, Adam bought me a Blendtec for my birthday. I asked for it specifically, over a Vitamix, based on reviews I had read. The deciding factor for me at the time, was that many people suggested the Blendtec was easier to clean.
Despite the Blentec's motor dying much sooner than I think it should have, overall we were pretty happy with it. It was used multiple times daily. I used it to crush ice and make coffee frappes, make batters for baked goods, sauces, purees, etc., and Adam and the girls used it primarily for making smoothies.
That being said, I didn't love cleaning it...but I probably won't love cleaning anything ever, to be honest. Food would get caught under the blade, and unlike our food processor, the blade wasn't removable. But it was not sharp, so I could often reach in and push food that was stuck with my bare fingers.
One thing I was very disappointed about was its ability to make nut butter. I had high hopes but after a few totally failed tries, I gave up.
The Blendtec had preprogrammed settings, like Ice Crush, Batters, Smoothies, etc. Sometimes they worked great for their intended purpose, other times, another setting would actually work better.
The Blendtec was also LOUD. Like really F#$*ing LOUD!
So a few months ago when it died, I decided to switch camps and try a Vitamix. We got the Vitamix Explorian E310 Blender, which Adam got a good deal on at Canadian Tire.
At first it took us all a bit of time to get used to it. It has no preprogrammed settings, so when I turn it on, I forget I have to turn it off, because the Blentec settings had timers and would go off automatically.
It is just as easy (or not easy) as the Blendtec to clean, however, the blades are super sharp, so you definitely cannot stick your hand in to clean it out.
Like all high power blenders, it is loud, but I don't think its as loud as the Blendtec, which is a welcome change.
I tried nut butter and the first time was a total disaster. A second attempt led me to realize you just can't more than about a 1/2 cup of nuts in at a time. Given its large size, I find this very annoying. I had 4 cups of almonds and it was extremely time consuming and messy to do so many individual batches. I am going to stick to store bought nut and seed butters for now.
The Vitamix we got does have a pulse button, along with the continuous power button, and a speed control. But we tend to just blast the shit out of everything on the highest speed.
Overall, I think I do prefer the Vitamix. That being said, it remains to be seen if it lasts longer than the Blendtec!