Positive: plenty of things to do other than downhill skiing such as cross-country skiing, skating, dogsledding ; no lift queues or crowded slopes (during New Year's week), attractive resort with many trees, pretty cabins and houses - no concrete blocks of flats like some resorts in the Alps

Negative: transportation between the two main ski areas is limited except in the morning and just after the lifts close. Outside of these times you need to call a taxi and they are not always reliable.
Staff in hotels and ski shops not very familiar with the area as they tend not to be locals. Best tip is to plan in advance what activities you want to do using the internet then go to Tourist Info office in the centre of Geilo to book and find out exactly where things are. Geilo is quite spread out and transportation can be an issue.
Though we had several snowfalls during our visit quite a few runs were closed. There are snow cannons but we only saw them used once. As is stood there were only enough runs open on the two sides of the valley to provide interesting skiing for 3-4 days. The skiing is good for intermediates - plenty of wide motorway type pistes, no mogels. The pistes with slalom courses and ski jumps were very popular with our young teens.