Alterra has a number of resorts they partner with but don't own (copper I believe is a partner resort owned by powdr).
We have had a good debate on PugSki at what Alterra really is trying to do, and I'm in the camp it has essentially just created another Vail with the twist of having more partner resorts. Whatever the case, I'm confident in saying that in Utah they have absolutely changed the culture at Solitude and DV as I know employees at both. Next time you're at an Alterra owned resort, ask the employees that have been around a while and personally ask them. In Utah, the overwhelming sense is that Alterra and Vail have both changed the culture after acquiring a resort.
Now one organization (perhaps Vail??) might be even be more controlling over the individual resorts than Alterra, but the overwhelming consensus at least in Utah is that both organizations have dramatically changed the culture at the resorts they have acquired.
Mostly people prefer working under previous ownership, but there has been some benefits. For example, when Vail acquired PC there was more working capital available for spare parts, etc. But overwhelmingly the employees I have spoken to at DV, PCMR, and Solitude all say the culture became more corporate following the acquisitions and more "red tape" etc and less enjoyable to work at.
Whatever the case, my biggest beef isn't the existence of Vail and Alterra which both seem to do at least a decent job, but rather the fact they are monopolizing the entire industry via their large acquisition activity and leaving very few independents left standing. Every major resort in Utah is now either owned by Vail and Alterra, or partnered with them in some way which is disappointing to me.
I haven't come to a conclusion if one is better than the other, although on PugSki it seems most have a bias toward Alterra over Vail. I was trying to figure out if that was purely preference in particular resorts although you and
@David Chaus are making the case that you think Alterra resorts may be better operated on average.