is the catalan good?

The Catalan is a great opening but you might find it tough to play.  Black has quite a bit of say about how sharp/quite the lines get.  You will need to know your theory in the sharp lines and be able to grind in the slower more positional ones.  I play the QGD as black and am always happy to see a Catalan since white usually goes wrong pretty early on.   

You can always expand your Queen's Gambit repertoire if you are interested in trying something new.  There are plenty of plans available in the exchange lines, not to mention 4.Bf4, 4.Bg5, 4.e3, etc.

It's a good opening, but one of the most complicated, theory-intense, and vast openings in chess. Like @ShamusMcFlannigan said, some lines are very positional in nature while others are extremely sharp. To play it effectively, you need to know tons of little motifs and maneuvers to keep your LSB active.

If faced with 1. d4 nf6 2. c4 e6, I will play into a Catalan, but if faced with a 1. d5 move order, I play the Exchange variation of the QG. 

All that became a little bit too complicated for me, which is why I play Colle and Torre instead with 2. nf3 move order instead of 2. c4

I did half of the quickstarted and the modern benoni chapters of the catalan got smashed in a few games and went back to my 1c4 stuff. Best to finish any 1d4 or 1c4 books befour jumping into the catalan. Ill study a few more lines of it here and there but im making my other books my sole priority befour i start a new one

im not sure if i should learn it

I think a good way to play the Catalan to find a way to make use of the fianchettoed light squared bishop

*is to find a way to make effective use of the fianchettoed light squared bishop. This I think is the key with Catalan