If you’re looking for a new smoothie-maker in your life, we recommend that you think about size, speed, and settings. It doesn't hurt if it looks the part too.
Size
NutriBullets are great for single servings. Their products come with 24 oz or 32 oz cups, the ideal size for 1-2 servings. The KitchenAid and Vitamix can make enough for 4-6 servings, so think carefully about how much you plan on making.
Speed
Some smoothie makers will have variable power, others will have one speed setting. Manually changing the speed means that you can control your texture a little more.
Settings
If your blender is one with different settings, you can tailor your blend even more. These appliances tend to be more versatile, where blenders like the NutriBullet Pro 900 specialize in smoothies.