Whether you choose a slow or fast juicer, they do the same thing. They extract the pulp from the fruit or veg, leaving you with just the juice.
A blender processes the whole fruit or veg, including the pulp. This makes a thicker drink (aka a smoothie).
Some juicers do more than just produce juice. They can also whip up nut butters and milk, sorbet, ice cream and pureed baby food.
Blenders tend to be more multifunctional than a juicer. As the name says, they blend and liquefy ingredients to make milkshakes and smoothies. They can also make great purees, soups, dips and nut butters.
If you just want your morning OJ fix, a juicer is probably best for you.
If you want to whip up smoothies, milkshakes, soups and more, opt for a blender.