I believe you'll find it's more like HomeAway than TripAdvisor. Bookings come directly into MyVR, and I don't think Booking.com has "inquiries". I'll ask someone from our channels team to point you toward some content on Booking.com, or perhaps some other users can chime in. Booking.com has been our most recent channel launched and is already a top channel. It performs really well in some geographies. Believe it's very necessary to keep your calendars up to date religiously on Booking.com, so you'll probably want to have that channel managed by the same company as your others (whether it be MyVR, RedAwning, etc) and not rely on ical. Although, that's really becoming true of all channels these days... channels aren't as forgiving about inaccurate calendars or low conversion rates.
FYI I think TripAdvisor will see some improvements in its connectivity with our software in the future. They've been investing in their connectivity (finally) and I'm excited about the potential there.