I went to Leysin in March 2010. It's small, quiet, and like the rest of Switzerland, expensive.
Transport is a cinch as Leysin is reached by a cogwheel railway from the nearby town of Aigle which has regular intercity connections to other Swiss cities, most notably Geneva and it's airport.
Leysin is a medium sized resort and I would say aimed at beginners and intermediates. There is only one black run which is not too demanding. I would classify myself as an intermediate and I managed to do all pistes several times in two days, so I would suggest Leysin is a good place for a short break rather than main holiday. Lift pass prices are at the higher end of reasonable, close to what you would pay across the border in Austria, but the prices of food and drink on mountain are extortionate. This is definitely one resort to take a packed lunch for the day. Leysin is very quiet at night and aimed at families, not the party crowd.