I'm heading to Vail with my kids for our 3rd Spring there, and the snow has always been fine that time of year. This year we'll be there from 4/7-16. I think it's a good choice since they usually have decent snow that time of year, and the Summit Co. resorts (which have more elavation) are a short drive away if Vail has poor snow. It's still early to forecast how April will be this year, but with the type of snow year CO is experiencing this season, I think it will be another great Spring to be there.
That said Utah's LCC resorts would be a good choice as well for that time of year.