The range in the nutritional value of store-bought juices is massive. On one end, you have "fruit drinks" with barely any actual juice in them. On the other end, you have fresh-squeezed, 100% preservative-free juices like Odwalla® and Naked Juice®. But no matter which you choose, it's important to remember that it's never going to be as healthy as whole fruit. And if you're trying to lose weight, it's a flat-out bad idea.
First off, it's been stripped of fiber, so you absorb it faster, which makes it more likely to induce blood sugar spikes. Secondly, you consume it faster and it's less filling, so you're more likely to drink more.
There are a few instances when juice is okay. For example, a home juicer can make predominately veggie-based drinks that are loaded with vitamins and minerals and lower in calories. If you're using this as part of a supervised juice fast, or you're trying to target a particular nutrient while concurrently not trying to lose weight, go for it. Otherwise, it's simply not worth it.
If you buy it, go fresh-squeezed, but you maybe better off just skipping it entirely. I still drink it.