First of all, thanks for the plugin!
1) I noticed a problem with the booking dates. They are entered wrongly in the database.
For example, if you enter April 17th for the arrival date and April 18th for the departure date, the results show the availability for April 17th only (which is good as we want to book the night of April 17th).
But when you make the booking, 1 room is removed from both April 17th and April 18th inventory. So for now, I have to edit the bookings manually in the admin panel and remove 1 day in order to show accurate availability results. (ie. Change the booking from "17 April 2014 - 18 April 2014" to "17 April 2014 - 17 April 2014"). That's not very convenient.
2) There's also another issue I noticed. Let's say we have 5 rooms of the same type available. Someone books 1 room of this type from Apr 17th to Apr 18th. If someone else wants to book another room from this category on the same dates or on dates containing Apr 17th, it is not possible even though there are 4 rooms left.
You get an error when validating the booking form "In your selection there are dates when the room is not available. Please select only dates available for booking".
I am not an expert in PHP, but from what I understood in the code, the booking can't be confirmed if there are other bookings of the same room ID, on the same dates.
I just removed that part of the code from shortcodes.php, in order to make it work for now.
I hope you understand what I mean. Maybe you can look into that for the next release.