I've never hears of the one you use Chris. Those that Wurger uses are very good, and, like Lucky, I use Milliput, and have done for over 30 years. I'd tried virtually every filler available until then , but, of course, things have changed a lot since the '70's! Some of the ones available now aren't available to me locally, so I stick with Milliput, which is very versatile, and can be moulded, drilled, tapped, applied 'wet' as a thin bead etc.
Of course, the choice of filler depends on the job, and I also use superglue as well as Kristal Klear, and talcum powder mixed with gloss clear varnish. The latter can also be used to seal, and then provide a glass-like finish on, balsa wood when making moulds, or plugging large gaps, or scratch-building large sub-sections of models.