Comparing the Texas Instruments TI30XIIs calculator to the CASIO, the CASIO might be more user friendly and easier to use fractions.  However the CASIO does not keep things in memory when it shuts off while the TI does.  The CASIO will also not give the correct answer to a few specific types of problems involving parentheses. For example (4)(4) divided (4)(4). Sorry I don't know how to put a divided symbol into this text.  The correct answer is 16; the CASIO will give an answer of 1.  It is easily corrected by remembering to put a times symbol between the parentheses, but it is still annoying that CASIO refuses to correct this logic error.