Well, my breed at the moment is a mutt, and there's a mutt for everyone! Except people who don't have any time for a dog . . . though if you really want a dog . . . I mean genuinely, really want a dog, there's almost always a way to MAKE time . . . or get help from a day care or dog walker . . . if not optimal, it gives a dog a home.
But that said, I don't recommend to people who don't have very "open" circumstances that they get a mixed puppy (meaning little puppy, not adolescent). There are just too many surprises: size, energy, temperment, instincts that could really mess up someone's life if unexpected, and mutts are always unexpected.
I met a young family in the pet store who had, I swear, one of the CUTEST puppies I'd ever seen. It black, fluffy, sweet as could be . . .you just wanted to take it and hug it. 7-8 weeks old, and breed unintentifiable and unknown. They'd gotten him from a shelter. Now, I'm very glad that pup has a home, but as I, and they, and some other people stood around and cooed at the little thing (his name was Onyx) the issue of what he was came up . . . and the truth was, no one had any idea. He looked rather Newfoundlandy to me, but who can tell at that age. Someone else guessed black chow mix, though he had a pink tongue. Lab mix. I can't remember all the guesses. But the truth was that puppy could have ended up anywhere from 50-150 lbs (it was obvious he was not going to be little), anything from mellow to hyper, from friendly to very wary . . . I wish them luck that he turns out in a way that is compatable for them, and if he doesn't, the love and moral courage to find a way to make it work. But I would not recommend to anyone without a lot of flexibility to take in a mystery puppy . . . besides, there are hordes of adolecent dogs that were given up when they stopped being agonizingly cute who need homes, and are much easier to evaluate.