The other question which is becoming more important as the concept of Concierge Lounges is rapidly being de-emphasized:

Which brands provide continental breakfast to elites? Which provide something better (buffet or at least credit towards better breakfasts)? Any exclusions? (e.g., Resorts, weekends, etc.)

In general, I find HH to be the best chain for this - although more properties have tightened lounge access rules a bit, a mid-tier elite can always get continental breakfast, usually get the buffet in the restaurant, and usually apply the continental breakfast cost to a hot breakfast. I'm not sure what the fine-print restrictions are, but I have never had problems at properties with "resort" in their title and I've never had any issues with weekends.

Marriott presents both of those issues - most full-service properties withhold the benefits on weekends and "resorts" withhold it in nearly all cases. The Marriott board has threads listing exceptions, but the exception list has shrunk in the past 1-2 years.