The base at Sunshine will be deeper but the surfaces will be similar. It depends IMHO more on the type of skiers in your group. At Sunshine the best preserved snow is on primarily intermediate terrain off Continental Divide, while Goat's Eye faces SW and surfaces are not great when it hasn't snowed in awhile. At Louise it's the frontside groomers that will be hard packed while the steep backside terrain preserves snow the best.
I will be passing through those areas in about a week.
Season length: 21 months, Nov. 29, 2010 - July 2, 2012
Days in one year: 80 from Nov. 29, 2010 - Nov. 17, 2011
Season vertical: 1,318K in 2010-11
Season powder: 291K in 2011-12