I highly suggest that you get out there, with some experienced pilots, and try flying both dual and quad line kites for a bit... then make your decission based on which way you'd prefer to go.
Definitely! I too have a large stable of kites becuase I didn't know what I really wanted. Tricks or precision? I find myself flying more precision now. And one kite that's built better for precision will not be better for tricks, and vice versa.
And several years of buying kites, I get into quads... lol- and found what really supports my zen of flying. Love my Revs. I still fly dual-line with my team, but if I'm flying solo, more often than not it's a Rev.
So, like Jinx said, get out there with some experienced pilots. See if you can borrow a kite and try it out. If you're only going to have one or two kites, you need to think about what you're trying to accomplish, even if it's just cutting circles in the sky (which is fun too!). Shoot- get matching kites and the both of you can start flying pairs!