1. If you want to take a chance at pulling a Jace, Architect of Thought and don't want to shell out $40 for a card, your only other option is to open lots of packs, and a booster box is ideal for that.
2. If you like cool surprises or want a bunch of what a set offers, even if the cards aren't selling for much, then a booster box I think is just perfect. I wanted to have a lot of artifacts and not just at common and uncommon only and opened a booster box of Scars of Mirrodin. I had a blast. I even pulled a Wurmcoil Engine !!! and a foil Molten-tail Masticore
3. If you really like one of the large sets, a common/uncommon playset is great. My only gripe is that the complete common playset is a ton of cards, and has playsets of all those commons that work for 15 minutes in limited and then are relegated to storage boxes to collect dust. I wish more uncommon-only playsets were sold. Still, once a set has been out for a while, these playsets are a great bargain. Even with a booster box you don't even get close to having a common/uncommon playset. With the box of Scars of Mirrodin I am still missing one common!!!
4. I am liking the intro packs more and more, and especially the battle packs. These out-of-the-box are a little weak, but all the fun is in opening the packs that come with this product and boosting the content in the pre-made pack.
Even though ebay sellers and the online bots perform a needed service, when in doubt, I am all for sealed product untouched by non-Wizards.
