The ability to book a specific room is a big plus for sure. But the one time I attempted it, I lost it anyway due to staying fewer nights than first booked. Found this out in advance and chose to stay elsewhere. The ones where you can't book a specific room, all but one time, I researched the hotel/rooms and requested specifics, emailed to confirm, etc. I'm sure I annoyed the heck out of front desk/manager, but being the squeaky wheel showed results.