We are on our 3rd Boxer, Enzo. We adopted him last year(newlifeboxerrescue.com) right around September. He's a bit older (just turned 6), so he's wayyyyy more mellow than a puppy or younger Boxer, but I can tell you that he still gets hyper, still gets into trouble, but is also one of the most loyal, loving, chill dogs that I have ever had. My parents were always Lab people, they had 4 labs over the time I grew up. Ever since we got Enzo they have been swayed into Boxer consideration.
On that note, let me tell you about Enzo. He was rescued from a dude in MA who kept him either locked in a crate almost all of the time, or tied to a tree all the time when the weather permitted. As a result, he took a LOT of work to re-socialize, work out some bad behavior, etc that was caused by years of not getting the interaction he needed. Boxers are family dogs, they need to be with you all the time. They will be attached to your hip or your SO's hip, or the hips of the kids, or if they could, laying in your lap. You will have a very unhappy dog if they are alone all of the time.
My advice is adopt one if you aren't around enough. Boxers remain puppy-ish until they are almost 3 years old. So basically, it's like you have a giant, strong, stubborn puppy. Also, crates... they don't always hold. Our last boxer broke out of his great on several occasions via strength and determination.
As far as their personality, they seems goofy (and they are) but they are also extremely smart. All of ours have been almost too easy to train, but they also learn things on their own for better or worse. Enzo has taught himself how to open doors, specific cabinets where we keep things, how to open the fridge, etc. Also, this will sound weird, but they seem way more tuned in to the way you're feeling, and almost hold grudges or act sad if you yell at them. If you've had Boxers, you'll know what I mean.
Anyway, shoot me a PM if you want. We've had enough of them to answer most questions. As health goes, they do have their issues (usual hip issues like other medium dogs, bloat is a serious concern and something you should read up on if it should happen, the white boxers have MUCH more tendency to go dead and/or blind as the lack of pigmentation is a genetic flaw - even though they're still handsome dogs).
If you adopt, there are plenty of Boxer-specific (link to ours is above, they were great), and they will match you to the perfect dog and if it doesn't work out, they will certainly take the dog back. Same cant be said for a breeder).
If you do go for a puppy, just know that Boxer puppies need A LOT of exercise. They can't be crated all day and exercised for 20 minutes when you get home. They need to be run, played with, trained, or they will definitely develop behavioral issues. Also, whether adopted or a puppy, make sure you really socialize them to everything - kids, dogs (large and small), family and friends. The only boxers I knew with less desirable temperaments were the ones that were poorly socialized. By nature, they look a little intimidating, but they are big clowns with big hearts. I never think twice about leaving Enzo with my sister and all of her kids. My nephew was terrified of dogs and since we got Enzo, they're best friends.
Let me know if I can answer anything else. I think most of the folks here have said similar advice.
EDIT: Oh and someone mentioned higher rates of cancer. This is true from our experience. Enzo actuall lost half of his back right paw and some toes right when we adopted him due to a cancerous growth that would only be stopped via amputation. He's had no further issues or developments (knocking on lots of wood).