Opimator... meh. Not my thing, but others like it.
Three Philosphers is typically classified as a Quad, not a tripel. It's damn good, too. I hope you enjoy it.
Truly, I'm not sure "Quad" means anything, other than being higher ABV than that same brewery's tripel. There are established methods of making, and taste expectations for Dubbels and Tripels (see my previous post about type of yeast used). However, there are only a few Quads on the market, and I think it's a fairly new thing, versus centuries of establishment in Dubbels and Tripels. That said, most Quads do have a similar taste and color, being darker and sweeter than a tripel, almost a more nosey Dubbel, with much higher ABV. I suspect a lot of them start off as a Dubbel with more sugars, but the wine-maker's yeast used to make Dubbels won't get you much past 8% - 9% ABV, so they must be using some other yeast or trick to push those ABV's up to the 10 - 12% range.