For exploratory work MATLAB and the MATLAB IDE are pretty good and shorter scripts are fine. However once you start trying to write actual programs and pass 1-2 kLOC or so, MATLAB just gets more and more painful.
I don't know that that's strictly true but it gives you a general idea for why things are the way they are.
Nothing beats Matlab/Gnu Octave for me when I just want to make some quick calculations.
Though you can also use 'import' to keep the namespaces separate.