Looking at your screen name, I am tempted to start out with something like:
"First, you have to be one with your paper ...."
Roll paper can be very useful, in that it allows you to cut different sizes from the same roll. A couple of friends and I are sharing a 30" roll that allows us to take off a variety of different sizes, as our needs require.
You need to approach cutting the paper with a fair bit of planning. Some guides and clamps and movable stops are handy. It really helps to have a rotary cutter big enough to handle the width of the roll, but you can do a lot with a mat cutter and a careful hand.
The biggest downside? Dealing with the curl.
There are roll paper cutter/dispensers that used to be used in commercial labs. They would be great to have.