Dear Decaf,
How amazing it is to read this!! I applied for the same programmes and had to make the same decision (through in two more schools into the mix and I found it nearly impossible!).
I know exactly what you're going through. Ultimatley I decided on McGill's programme for a number of reasons, and while they're personal to me, they might be of interest?
To give a bit of background, I'm from the UK, about to wrap up my undergrad here and am making the move all the way to Canada (to a continent I've never been to before)!
While I was offered far more money at Dalhousie (and in fact I was offered yet more in the form of a scholarship today which doesn't help the decision-making process!), I chose McGill primarily because:
a) Faculty - after chats with an incomprable amount of people I realise this is THE most important decision for Grad school, and while you say you'd be on the Non-Thesis programme, it's still so important to factor this in. McGill musicology/theory professors are excellent and, speaking as someone from another continent, loads of them are renowned across the pond.
I've got a UK-based scholarship which means money isn't an issue - finally!
c) Montreal seems quite a vibrant and dynamic place - though I'm sure you know about this more than I do. I think the opportunity to enhance/maintain French is fantastic and relevant to musicology. Plus, OSM are having a new concert hall built coinciding for when we start! A great cultural centre, non?
d) The facilities at the Schulich seem pretty amazing. Admittedly, it has to cater for a larger student base than Dalhousie, but the facilities, so I am told, are quite a bit better. Add to the mix that they have 600 concerts per year, a 3 story library etc, and I think you'd have access to better facilties than you might expect at Dal.
e) Name. I hate myself for writing this, but as a junior professor told me here (he left graduate studies at Harvard for Toronto for many different reasons) while name isn't everything, it does count for something. McGill's 'brand' is very exportable. So if you choose Dal (which is arguably less well-known) you should have solid reasons for this.
At the end of the day, it has to be your decision of course. I applied to Dal and I think that some of the faculty there are excellent (Dr Joubert comes to mind, as does Dr. Baur - but as you say, he's on sabattical for an entire year). I think you'd have a great time at Dal if you pick it! Though it would be lovely to see you at McGill!
Hope you are able to pick soon. Having been through this agonizing decision-making process myself, I can definitely sympathise. I think your main priorities should be a) where do you want to go after x or y university; and what place is best served (facilities/faculty/location) to effect this?!
Let me know how you get on and good luck,
Best,
Harry