further research required?
Well, the thing about Orval is its secondary fermentation in the bottle, which means it can vary a lot depending on the age of the bottle and how well it's been looked after. So yes, definitely try another one - it may be that you've had a duff bottle.
The other thing about Orval is that it's a supremely well balanced beer. Malt, yeast and hops in perfect harmony. It's not one of your edgy, experimental, break-all-the-rules Mikkellers or overblown, mouthy, all-fur-coat-and-no-knickers American Hop Monsters, it's just a well made, complex but well-rounded Belgian ale. If you're expecting something "out there", you may well end up disappointed.
Of all the world's supposed "classic" beers I've tried, only two have truly lived up to their reputation and my expectations - Orval and Rodenbach Grand Cru. Orval would be my Desert Island Beer.