That's why I prefer 5 stock.  It really separates out luck, adaptability, and endurance. 

Low stock favors someone who is lucky.  You make a single mistake or accidentally push the wrong button and that could be the end of the match.  Everyone is going to make at least one mistake a match so low stock doesn't really help.

High stock favors someone with adaptability.  Sure your tactics may work against someone on the first life or two, but what about the 3rd?  4th?  5th?  If the other player can't adjust to them by at least the 3rd life, the match is over.  However, the extra stock gives the player that chance so you need to be ready to adjust your own strategies as the opponent learns to counter them.

High stock also favors someone with endurance.  Getting frustrated is part of the game.  If I can frustrate you, I can win.  Endurance means that you can roll with the punches and keep going even if you're down a life or feel like everything is going against you.  Earlier today, my Pikachu faced off against Riot's Pit at the end of a Brawl.  I had at least 80% damage and 1 stock versus Riot's Pit who had 2 stocks.  I made the best of a bad situation (and won).  We won't talk about how I won though.  ^_^

To me, the more stock, the better.

good players adapt on the fly with any amount of stock.

 Luck in brawl......lol.

Does any of you guys have the problem that when you are losing in a duel you get frustrate and stop trying hard?I just ask this because I hate playing in duels with more than 3 stocks,today I played a guy that mains mario and I beat him once but then we played with 4 stocks and because I killed myself I got frustrated and stop trying that hard and I lost with only taking him 1 stock but that guy wasn't as good as anybody here I know I could have beat him it's just that I don't like playing long duels I get tired,I think I will start to get use to long duels.

 Edit;Tao I wasn't the one who didn't let you in it was my oponnent.

I was :]