They work OK. I have a few 18" in my shop, use em to cut film. They can't really do more than 2 or 3 sheets at a time without binding.
Go find a friend at a small paper printing company. Pressmen like coffee, beer or pizza, and sometimes will trade for 10 minutes of their cutting time. I just show up at my local letterpress shop with a few large coffees, and the owner points to the cutter and says "if I don't have to get up, use it as long as you want"
you can find a lot of places in town that probably have a nice heavy duty paper cutter. I get my paper cut down at a local copy shop...the guys doest even charge me cause he can use the excess paper...really nice guy.