I started messing around with my TI-89 calculator and interfacing it to my computer. This is a really versatile calculator and I use it a lot in my tutoring business. The only gripe I have is that it is hard to read some of the writing on the keyboard because it is gray in color and the yellow and blue writing does not contrast well. As with any small device, the real limitatiion is the I/O. A tiny screen is the biggest problem. If they could make it higher resolution, that would be a plus. Regardless, it is quite useful.