I am on laptop for convenience, although I really don't mind too much.
I find it really annoying though when people slam laptops for no reason and say how they are 'slower'.
I use a gaming laptop just sold my desktop on PC, but i must say i still use a desk and external monitor sometimes depending on how competitive when i get.
Desktop for a few reasons, easily upgradable, more power over a laptop and a few more. I'd use laptop more often if it was easy to slap and GPU in it and upgrade the CPU etc.