Indeed, it has been one of my favorite Belgians ever since I tried it for the first time a few months ago. It has a somewhat "acquired" taste... almost slightly "vegetative"... what I would describe as a faint "cactus" flavor (a much fainter version of what you taste in good tequila). And yes, one great thing is that it's not overly sweet like some cheaper "Belgians".
Unfortunately, the Westmalle tripel is not quite as distinctive in my opinion... more like a run-of-the-mill decent tripel.
Edit: just saw your thread on Orval... another I like... great taste buds apparently think alike. Orval has that earthy-sweaty flavor, but also some distant raisin-like tones underneath a dry finishing champagne exterior... along with the coarse head, a very primordial kind of sophistication imo. Not anything like a recent American "Belgian" I had which tasted like liquid raisin (it even had raisins on the label.... subtle! If anyone can tell me what that beer is please do since I forgot the name).