There are essential differences between limit holdem and no limit holdem besides the esthetic one that involves the presence of absence of limits.
For once, when you are playing no limit holdem you play a more methodic game. A skilled player can easily develop and apply strategies in no limit holdem, much easier than in limit games. If you are a beginner then no-limit is not the game for you, but limit is the perfect one. Limit protects new comers and doesnt let them loose too much. If you are a skilled player and you encounter a beginner in a no limit poker room then you can easily take advantage of his presence and make a lot of money out of him. As they say, sky is the limit and here the sky is the beginners stack. Big mistakes are paid dearly in no-limit, you will just go all-in and lose all your stack. But in limit if the same mistake is made then it is not such a big deal, it just means that if you pass a few mediocre bets you will be right where you started.
In no limit holdem you can use psychology more often and it turns out to be more reliable. This happens mostly because in no limit more money are involved and the risk of losing them all at once...