colle or catalan

which opening is more aggressive or flexable and why ?

The catalan is definitely more agressive and flexible than the Colle. The Colle is very rigid: d4, Nf3, e3, Bd3, c3, Nbd2. On the other hand the possiblities, variations and transpositions possibles in the catalan are by far many more, and I'd also say better.

The Catalan is an awesome weapon to take the initiative from the first move, and outplay your opponent sometimes positionally, but sometimes also tactically. That's why it's a so dynamic opening.

If you don't play it, I encourage you to give it a go. You'll like it.

You can't play a single Colle against all move orders.  I usually play the Colle-Zuckertort but only when black doesn't fianchetto or play the light squared bishop to the kingside.  In those cases other ideas are needed.  The KIA maybe the easiest system to play against most lines.  The Catalan is perfectly good as evidenced by it's use in WC

*edit*

I should add that when you play 1.d4 2.c4 you may not get to play the Catalan, things like the QGA, Albin's Counter Gambit, and the Budapest Defense all have to fit into your plans.  2.Nf3 does avoid that theory

Estragon's advice has merit: play the Queen's Gambit first, become comfortable with it, then the Catalan can become a potetnt weapon.

I play the Catalan and find playing against it difficult. It is powerful and potent.

The Colle is a passive-aggressive opening for those that eschew opening theory. It deservedly lacks the respect merited by the Catalan, and you won't see it at GM events with any frequency.

Ziryab,

I grant you that in GM play you won't see much of the Colle lines but that doesn't mean there's no opening theory.  If you play the Colle-Z without any theoretical knowledge you will almost always lose that light squared bishop. 

It is true that in absolute terms the Colle will grant black equality but against higher rated opponents it is probably better to play a comfortable line with equality rathern than losing in the opening.  I can keep the computer at bay past move 20 with a Colle-Z, I'm sure in most QG lines he would be beating me in the opening.

But the Colle set-up is also quite instructive and overlaps with several ideas in QGD, and Slav lines, and even a few QGA lines.