Are you afraid of heights?
Me too, so I prefer bouldering. I was so weak and sore after I first started, it's getting better now :)
I am fortunate that I am not afraid of heights...I am however, a little afraid of my hand and arm strength failing me and crashing into the wall! :-)
I tried bouldering but didn't find it as satisfying as scaling the wall. It was really cool to watch the people who were good at it do it though!