I have used the Fiskars rotary cutter with the funny shaped handle for years. It gave me the least problems before I had my carpal tunnel surgery. I also have a blue cheapie that came in a starter kit (mat, ruler and cutter, which I bought for an impromptu class), a green Clover (which was a gift) and a yellow and black Olfa (which I use strictly with a pinking blade). All three of those have a straight handle, which is less comfrortable for me, so I don't use them often (or if my Fiskars has decided to hide from me). All four use 45mm blades and have to be manually closed after each use. If I was going to get another one, I would probably go with a Kai.