Jan, Yes, I experimented with the symbolic reasoning of Mathematica a bit a few years ago. I could not get it to converge to a solution as easily as it seemed to get hung up on local minima. There also weren't a lot of options for objective functions, IIRC. It really is much like the solver in Excel, which has user-defined objective functions and is less prone to local minima (Excel also doesn't crash or lock up your computer as often as Mathematica, but that may just be me). Neither is as free-form as Eureqa as both Mathematica and Excel Solver require a structured symbolic template to run.
I really should look at this again as I have a Alpha Pro subscription for a little while yet. There is a also a pricey subscription to a Pro version of Excel Solver, which is also kind of tempting -> https://www.solver.com/pricing-excel-product-software-and-support. Curious as to what this will do beyond the free version.
Do you have any strategies for success based on your experience? Thanks!