The main appeal of Big White is the great selection of slopeside accommodations. There's an impressive selection of large slopeside chalets with true ski-in/ski-out access, outdoor hot tubs, etc.
In terms of challenge, there's very little white-knuckle terrain if you're a strong expert skier, but the terrain is pretty good. The bowl under the Cliff Chair is fairly steep (although short) and there are some fairly steep runs off the Falcon chair as I recall. I love tree skiing and you can pretty much ski the trees from one side of the resort to the other. I was always able to find some nice tree shots with good snow. As a MRG skier, you should appreciate that. One downside is that it can get pretty foggy at the top of the mountain at Big White which will render the Cliff Bowl unskiable. That happened a couple of days when we were there.
As a point of reference, I take a couple of trips out west (I live in NJ now) each year to ski the steeps at places like Big Sky, Cottonwood Canyons, Mammoth, Jackson Hole and Whistler. One trip is pretty hard-core skiing with the guys and the other is a family trip with my family and my wife's sister's family. One year the Canadian side of the family wanted to try out Big White. I shared some of the concerns of the other posters on this board, but they were unfounded. When you combine the good skiing (like I said, no scary steeps, but decent stuff, particularly in the trees) with the awesome slopeside accommodations, it all adds up to a nice trip. By the way, they have a good terrain park, if you or your kids are into that scene.
We ski all over Vermont as well and based on my experiences in Vermont, you won't be disappointed with Big White. In the end, it depends on what kind of skiers you have in your family. If they're all hard-core and you want to go to the BC area, go to Whistler. Big White is a great all-around family destination though. One final point......with the exchange rate where it is, you may find better deals in the States than in Canada if you're trying to save money.