So last week I purchased by VERY FIRST ROTARY CUTTER! I went in to look at Olfas, and came out with Fiskars. The girl I talked to had very small hands like mine, and said that if you're cutting a lot, it's annoying and painful to hold down the olfa blade the entire time. Fiskars actually holds the blade out on it's own, so you don't have to worry about that while you're cutting. (It goes without saying that you should snap the blade back after every use.)
It's fabulous! I was timid to give up my trusty scissors, but I'm glad I went with Fiskars. I highly recommend it!