Probably goes without saying, but it's generally proportional to the price of the box. The cheaper the box, the harder it will be to pull a real high end card. Basically, just buy what you can afford. Everyone likes different products. Topps Chrome is probably the most popular for less than $100. Having said that, it's under $100 so the chances of pulling a huge hit are minimal, but the overall value will be among the best.
I usually buy a box or two every Saturday, so just be prepared- for me, it feels something like: 75% of my boxes are busts, 18% are just OK, 5% are wins, and 2% are the monsters that are the reason you open boxes in the first place.
So basically- chances are you will get far less in the box than what you paid. As long as you know that going in and are OK with it, you're good. If you would be upset when you don't pull a huge hit, just buy the singles and let other people bust 'em for you.
If youre on a budget look at the price per hit. If the box is $100 with 4 guaranteed "hits" your looking at $25 per hit. Something like Momentum is nice because while the box is $150 you get 10 hits or $15 per hit. Generally (and I say that with hesitation), the higher the price per hit the better the cards and generally the better the hits. That is a generic though. I've had some amazing Rookies and Stars boxes ($80 per box) and had some flat out putrid UD Exquisite boxes (well over $400 a box).
Exquisite boxes are usually among the least risk of getting a bust of a box because they are all hand packed by an actual person who attempts to make sure that doesn't happen. Which is the way it should be for $500+ if you ask me. :-)