Since starting with RMS just a few month ago our main complain is the Booking engine 's friendly userness. we were with smaller less complex system before and their Booking engine was much nicer (display, font, customisable buttons....)

The Availability Calendar needs to be visible and accessible from the HOME page directkly with clearly visible "available room nights" regardless of the room category.
Currentky you 1st enter your dates then once you have all the rooms displaying you can go in each category to see the Availability calendar. Not sure how many guests take the time to go in each of our 7 categories to look up availability Calendar.

Also should need arrows next to the Months to make it easy for guests to swap to other month - a few have called to say they couldnt find how to go to another month.