The Abbeyglen Castle Hotel is gorgeous and really unique. We booked our stay in the economy room the day before we arrived. As mentioned, these rooms are very small and the bed takes up majority of the room but the beds are very comfortable and there is a bath tub which was a very nice addition.
Something to note is that the walls in the economy room are very thin and we could hear our neighbors the entire time, especially when they were using the bathroom.
The castle is a 10-15 min walk into the city Centre and we enjoyed walking around and grabbing a bite to eat.
The one downside to our experience is my wife and I booked via the app and somehow accidentally forgot to change the setting to two people. We checked in (both of us) just fine and it wasn't until the next day at checkout that we were notified that for an extra person, it would be an extra 49 euro. That means the economy room is about 113 euro for two people. I would say it is still worth it for the experience of staying in the castle but we think we should have been notified of the extra charge during checkin just for courtesy sake.
Try and get there before 4pm to enjoy the afternoon tea and biscuits and join the main room for the champagne toast at 6pm. Breakfast was great and the premises of this place is spectacular.
You can tell the hosts really enjoy what they do.