Wow, for once, I might actually be able to offer some useful advice.
I actually haven't been out there in 3 years, but, if Kjell (pronounced 'chell') Peterson is still there, he gets a huge thumbs up from me. That said, the last time I was out there, I elected to save some dollars, and just took a group. I ended up with a younger guy (sadly, I forget the name), and three other students. I received what I considered to be an outstanding lesson/ workout, and it didn't cost that much at all. My son (age 6 at that time) also recieved some great instruction in the kids program.
A short story on the kids program. The year before, we had taken him to 7springs, PA with us, and he spent about half the day inside, watching videos and playing. There were about 8 other kids in his group, and they never left the short base/kiddie area. Before taking him out to Big Mountain, I asked what they did in their kids classes. Their answer was ski, short lunch, and ski some more. They actually thought it was a rather odd question, until I related my previous experience. There were only 3 other kids in his group, and on the second day, the weather cleared, and the instructor had them all theway at the top of the moutain, where they could see the peaks of Glacier National Park stretching off to the east, and clear into Canada on the north. He developed a love for skiing that day, and couldn't stop talking about his experience. They really did a fine job with my son.
Big Mountain is not one of the major destination resorts for US folks. It is a bit off of the beaten track, and takes a little extra effort/dollars to get there. Oddly, they do get quite a bit of international traffic, especially from Great Britain. That said, it is a truly great mountain, with very laid back and helpful employees. The only down side are fog days. I doubt you would go wrong with almost anyone on staff, but Kjell is a great guy. You might also inquire, if you have a specific need that you would like to be addressed. Expect to have a great time, and fall in love with the place. I only wish I had the dollars to make it happen this year.
Have a great trip, and please post a trip report.