The thing about the two is that they tend to fall along a spectrum:
Balanced But Boring <----------------------------------> Exciting but Unfair
This is a bit of an oversimplification, of course, but it's still highly applicable to a wide variety of PVP games. Before we go into why/how/what to do about it, let's talk about another aspect of games in general: skill and luck.
Skill and luck are the two basic things that can determine who wins a PVP game. They also kind of exist on a spectrum, but only in a strange way. Skill and luck can't coexist inside of a given mechanic: at any given point in time, you're either able to influence the outcome of a given in-game act with your skill, or it's left up to luck. But in the gameflow as a whole, it's an everyday occurrence to see several tightly-related acts, some skill and some luck, all influencing the same overall result.
In a very real way, the excitement of a game is based largely on moments of luck within the context of a mostly-skill-based game OR moments of skill in a mostly-luck-based game. For example, a game like chess that is 100% skill based has drama in it, but the drama generally comes in response to a truly amazing or truly horrible move -- the player doesn't realize the drama until after the move has registered in the minds of the observers. But in a game like Magic: The Gathering, the drama frequently comes on one specific draw that might change the course of the game entirely, or might not. M:tG is mostly a skill-based game (though the skill comes mostly outside of the context of a given match, which leads to other problems we'll talk about in the next post.) The luck that impacts the game, however, is profound when it does occur, and that makes the game exciting.
So, back to the original topic: boring vs. unfair. Let's look at a game that was never intended to be PVP, but that players can't help but getting the rulers out and measuring themselves over: Dungeons and Dragons. In 3rd edition D&D, the problem was that the game was unfair. Low-level characters were tolerable, but well-played moderate-to-high level spellcasters dominated everything whereas nonspellcasters basically sucked. There was no amount of skill in character building that could make up for the discrepancy in the rules, and people hated it.
Then, 4th edition happened, and the opposite occurred: Suddenly, in the paraphrased words of a friend of mine, "the exact thing you chose to do on any given round didn't really matter anymore." All of the abilities were so carefully balanced, and all of the combination-and-permutation crap that made 3rd Ed so lopsided was
The optimal balance point, then, has to come somewhere in the middle. Somewhere where both skill and luck have a part in the action, where choices the players make are meaningful but the results of those choices don't feel arbitrary.
You can't play Flip A Coin or Soy Mas Fuerte Que Tu and have it be a fun PVP game. The third option is Rock Paper Scissors -- and next time, we'll talk about how to make RPS fun on every level.