I switched from the TI 89 to the HP 33s. There have been a lot of complaints from older HP users about the new HP 33s, but I like it. I switched to RPN, which I now don't know I ever lived without it, but it has the TI method of input if you don't want to switch to RPN. It also has a nice equation solver and has the ability to write some programs in it. When I found out about the new calculator policy I was at first very upset, but then set off to learn a new calculator. I first went with the TI's as that was the most logical transition, but I was unhappy, mostly with the buttons. They had a squishy feeling and I had to be very conscious about actually making sure the button was pushed. The HP buttons actually give you a little click to let you know you have the button pushed and recorded the number. You might think this isn't that big of a deal until you are crunching away and realize that you miss inputed a number (if you realize) and have to start over. The RPN is nice also because it allows you to solve equations and then pull the answers to use in later calculations without storing to a variable etc. I never really looked at the Casio, but I have been very happy with the HP.