Great atmosphere, nice people, skiing can be anytime from November to May
Very unreliable snow, extreme weather, when good - fantastic, when bad - hmmmm
CairnGorm is the ski area above Aviemore, which is a popular year round resort. There's a lot to do here and skiing and boarding are a small part of that so when you book a trip here you should think of it as an all round outdoor holiday and not expect great skiing all week, it's not like that in scotland. But there's a good vibe to the place, good nightlife, dozens of alternative activities like distillery tours, hikibng, biking, fishing, clay pigeon shooting, reindeer herds, climbing walls, steam trains, indoor pools, it's a really good place. It is also fuin to arrive by train - you can even get overnight sleepers from London for as little as 19 pounds all in (Google 'Scotrail Bargain Berths') or cheap glights to Inverness with Ryanair, Flybe and Easy Jet from most Uk airports then its a 45 minute bus or train trip down.
Anyway, the skiing! Aviemore gets real extremes of weather. It can be very cold or very warm in winter so you might need like Arctic level proterction or its too warm for snow in January. Then it can get very windy, it has the record for the windiest place in Britain. So most times there's limited skiing and conditions aren't great. But sometimes there's great snow, no wind, blue sky and it's the best place in the world. The only problem is those days, if its a weekend or school holiday, thousands of people arrive so you spend most of you day queueing to park, queuing to rent, queuing for the lift, on a crowded piste and you wonder if it is worth all the effort. The best thing is when you can ski mid-week on one of those days and you have the place to yourself. Everyone is very friendly and well behaved in lift queues - there is a real etiquette here and queue jumpers get a good telling off from everyone else, if not actually beaten up ;).