Kitchenaid blender.
This smoothie maker has a very solid motor that seem to last forever. I have seen friends who have been using Kitchen mixer for a couple of years now and it has never given them any problems. This particular smoothie machine has a high horsepower, which absolutely critical for smoothie making because you will want to crush the ice as finely as you can get. The drawback is its price. Relatively to the rest of the models in the market, Kitchenaid is more expensive. Hence, if you have higher budget and wants a more durable smoothie machine, the Kitchenaid blender is a good choice to consider.
BlendTec blender
Some users consider BlendTec blender to be the best but it is very pricey! This is the commercial strength blender that is used in many professional smoothie places like JambaJuice. Fortunately, Blendtec blender has a home model which is more affordable and is good for family use. The demonstrations I have seen is very good. The motor is able to blend the ice very well and it came out like a snow cone (shaved ice). In fact, the Blendtec will blend anything you put in it and the consistency is great. However, the price is really high, even compared to the Kitchenaid blender.
Magic Bullet smoothie machine
Magic bullet smoothie machine is a blender that is more basic than the other 2 models mentioned above. It works good but its biggest drawback is the cleaning aspect. Basically cleaning the magic bullet blender is a real hassle. Budget wise though, it is definitely cheaper than the 2 other models mentioned above.
Handmixer
This is the cheapest option and is good for people who don't mind putting in a little more effort in their smoothie making. Just go to the stores like target, walmart etc, and you can buy it. Using this handmixer, you can still blend stuff but using your hands of course. Then, all you need to do is rinse the mixer off. It stays by the sink, and is super easy and convenient.
In case you are not a smoothie fan, the smoothie machine can also be used for frozen margaritas (and of course other stuff like hummus, guacamole, protein shakes etc) In fact, beside smoothies, I always curious on what are the best blenders for margaritas. I am not promoting people to drink but they are nice to have after a week of hard work at the office.
Making margaritas is not really new. I have seen youtube video of people showing how to make margaritas at home. The process is actually quite similar to making smoothies. Hence, why not extend the usefulness of your smoothie machines?
