There's no set limit. It varies by property. The Terms say that in the absence of a club lounge you are "entitled" to a full breakfast entree, juice, and hot beverage OR buffet for two adults and up to two children including tax and gratuity.

Some will describe less positive experiences, but in practice I've found this to be a **very** generous benefit. At higher end properties, I've run up bills in excess of $100.... charged it to the room, and had it promptly/automatically removed from the final bill. In (rare) cases where something appears on the final bill a quick call to the front desk (or text at some properties) and it's gone. No fuss, no vouchers or coupons either, it's very discreet benefit, which I also love!