Sorry to be slow to reply Ruddles. Yes, as it happens Andorra was where I did my instructors.
I loved it! It's really a question of what you're looking for, how much you have to spend and when you go. Any resort is going to be busy in holidays and particularly half-term time is chaos. More than twice the price and everywhere is packed. Not my idea of fun!
Andorra is a lot LOT cheaper than Tignes. It's further south and not as high so it's not as snow sure but you can't forecast the weather 100%, there's always some luck. Andorran resorts (particualrly Pas and Soldeu) are almost entirely British so if you expect some culture then you're in the wrong place. Lots of Apres ski though so a party hard attitude is a bonus if you're there.
So overall re it being busy, can't say for sure but it's likely it was a case of when, not where.
Cheers for the reply
We're going for the slopes in the day and parties at night pretty much. Culture doesn't worry me much. I received enough 'culture' from the french in Tignes (french snowboard shops that don't sell binding screws....sure)
We're thinking Mid to late January next year for a long week pretty much