One of my friends prefers a variant term: "Balanced High."
Compare a fight between two boxers with gloves and bits, versus a fight between two trained swordsmen. In each case, the opponents are evenly matched, but in the boxing match, any given hit has a slim chance of taking out the other guy. In the sword duel every moment, every exchange of attack-parry-riposte is much more fraught with uncertainty, and so more filled with drama.
This friend of mine ran a d20 Conan game where people could swing giant swords that would kill you in two hits, but you likewise could kill them in two hits. Attacking first held a great advantage, as did finding ways to get in more attacks than your opponent. In 4e, by contrast, we're usually fine taking our licks, because we know that a single monster usually won't kill us for at least 4 turns, and we can heal mid-combat pretty easily.
My group generally prefers the former style, where combat is swift. Another DM, though, prefers more tactical combat, and since 4e combat usually lasts longer, it gives him more opportunities to develop tactics. But you can get a 'balanced high' fight even in 4e. Brutes work well for this, and if you make the whole party strikers, with no leaders, combat tend to rush toward climax.
What I don't like are fights where one person can win the fight in one round due to a good roll. Sleep and similar spells in 3e weren't "Oh crap, we're in a tight spot, time to do something awesome." They were "Well, that was short." That's not fun.
So swingy = 3e save or die.
Balanced low = 4e with lots of defenders and leaders.
Balanced high = a Stygian warrior bearing down upon you with a blood-slick tulwar