I'm using HandyCalc now, it's excellent and free.
But unfortunately, it do not support hyperbolic function (sinh, cosh, tanh, etc.), and it do not support complex operation (e^(i*π)+1=0, etc.), neither do matrix.
Arity is simply, powerful, but not as user-friendly as HandyCalc, it supports hyperbolic functions and complex operations, but lack many features that HandyCalc has.