I'll offer my advice:
I would only *ever* buy a booster box for one of the following two reasons:
1) You'll pull a higher dollar worth in cards than the box costs you.
2) The cards in the box are too hard/expensive to find in pack-fresh MINT condition.
In the past year and a half I've been back to the TCG, I have only bought a few booster boxes. I have bought several of the Black & White series boxes, simply because I could resell the contents for a considerable profit and then keep a few cards for myself. I also purchased a Legendary Collection box for a little over $200. It's my all-time favorite set and I figured with the price of Mint RHs, I would easily make my money back and have a blast opening it as well. Not to mention, cards from that era can be very difficult to find at a reasonable price.
Anyway, as far as HS Undaunted is concerned, you could get a complete set for less and you wouldn't have any extra cards you don't need. You'd also still need to buy singles after opening the booster box. I'd recommend buying a newer set (Boundaries Crossed comes out in less than a month), or buying one that is collectible and hard to find. That doesn't mean to go buy an EX Holon Phantoms box though. I've seen these go for $200+ and assuming you get a Gold Star (which is never guaranteed), you'd be lucky to get half that value in cards.
