Hate 'em

K 5
K 9 6 5 3
J 9 5
K 6 2
Q 6 3 A J 10 8 4 2
J 8 4 2 Q
------ A K Q 3 2
J 9 8 7 5 4 A
9 7
A 10 7
10 8 7 6 4
Q 10 3 Vul: No one

NorthEastSouthWest
Pass 1 Pass 2
Dbl Redbl 3 Pass
Pass Dbl All pass

I hate balancing bids. It's not just the frequency with which they lead to disasters. But the philosophy is all wrong. "Partner, we weren't strong enough to enter the bidding at the one level and we weren't strong enough to enter the bidding at the two level, so let's enter the bidding at the three level!" Make sense?
Oftentimes the apparent philosophy isn't so flagrantly wrongheaded, but remains questionable: "Partner, they're ready to drop the bidding at the two level, so we must have a favorable spot open to us." Oh? Is anyone watching? That was the question I would silently pose back when I did a lot of kibitzing. "Is anyone noticing?" I have always found such a high percentage of fizzles in balancing bids that I wonder how they keep their prestige. To be sure, I will grant that it's a lot easier to spot the disasters than the ones that work. The former show up at the top or bottom of the scores, while those that work would tend to be in the middle, or close to it. On the other hand, when you do find a balancing bid that works, I'd say 9 times out of 10, you've got a hand where one partner could easily have come in earlier with a simple overcall or takeout double. Or such is my belief.
Another part of the balancing philosophy that I find unappealing is that you're very definitely trusting the opponents. You're saying you trust their bidding skills so much that you now feel comfortable surmising on your potential (which you hadn't before felt comfortable about determining) and entering the bidding. And then the blindness to learning from observation. A pick-up partner informed me that he was looking for a regular partner for Friday. Okay. Now we have a hand where the opponents are willing to let the bidding die at two diamonds (my partner and I having each passed at least once), and my partner with a jack-high five-card club suit, vulnerable, ventures a 3 club bid, which leads to a three diamond bid and out. No disaster, of course. But those guys were missing a cold three no. "God, that was a risky 3 club bid. They could have buried us," said I. "I don't see anything wrong with it," said my partner, and I never saw him again.
I could have retained at least some respect for his acumen if he'd simply chuckled and said, "Yeah, I guess I did stick my neck out," or something to that effect. But he didn't even seem aware that over a piddling 2 diamond bid and a minus 110 or so, he courted a minus 800! Make sense? If you say Yes, I know a fellow who'd love to have you as a partner.
Oh, one more thing I almost forgot. I printed out the hand in two different directions. In the other, they got to their makable slam, which was butchered for minus 50 their way. And the scores? The balancing N-S pairs got a minus 13.03, while the guys that kept their mouths shut got plus 10.82. Which do you prefer?
[A makable slam? Yes, the cards are right for it, but just barely. Declarer must ruff a diamond and take the spade hook. Then if uncovered, return to the East hand and ruff another diamond, return to the East hand and draw the last trump. So it's hardly any wonder that declarers were going down in that bid. But in any event, that's another downside to balancing: that sometimes those guys won't make their bid. And South sure as shootin' couldn't make his bid here.]
The hand is also illustrative of a few other categories, namely Redoubles and Bidding in Competition, as mentioned above, and also my reference to Twenty as a key figure. North has all of 10 hcp's and he wants to drag his partner to the three level? Now, I've granted that with superfits, it's hard to put a ceiling on how high to go. But there's no evidence of a superfit here, not even a singleton or void in North's hand, and without a superfit -- and 8-card fits don't come close to that description -- and without a preponderance of the hcp's, I have always said that the two level gets risky, the 3 level downright dangerous. 'Nuff said? Is there any reason for North to figure his partner must have at least 11 hcp's?
Oh! One more thing: do your own research. I not only am not begging you to accept my word and observations uncritically, but invite you to do your own observing.