@farmerman,
Hi FM, I started out using PC's and worked with them for over 15 years (I was a Microsoft CNE for a while there), but ever since MAC came out with OSX (a proper UNIX based Kernel) I have preferred MAC's.
MAC's are far more stable, elegant and intuitive (they also retain their value better). The only advantage PC's have is that a majority of software is written for them.
None the less, MAC's have all the standard business and productivity software that PC's have (the major MS Office Applications are all ported to MAC).
When surfing the web on a MAC you sometimes run into a movie file or something which requires an MS program to view, but there are usually free downloads for the MAC which will handle almost everything (one notable exception being the new SPORE Game, which doesn't yet have a version which runs on the old (non Pentium) architecture of MAC's).
*IF* you have a particular program which you need (such as the math modeler and ROCKWARE programs you mentioned), then you should make sure there are versions of those programs which run on MAC.
Bottom line is that MAC's are as good, or better than PC's for a vast majority of applications. However, there are a few specific programs which happen to exist only for PC's, and if you happen to need one of those....