STK is a great toolbox, really. But I am one of developpers, so you wouldn't expect me to say otherwise, right ? @all STK users: please rate the toolbox as well ! Some interesting statistics are available from OpenHub.net (look for "STK" and "kriging"). Hope to hear from you soon on the STK mailing list :-)
This software is a competitor of DACE (another Matlab kriging toolbox) with extended features.