We use xolab to book our accommodation when we are traveling around Europe as well as within Spain so I can't think there is anything that would be bad about this product! It has all you need to manage any type of travel related service whether it’s hotel reservations, car rentals etc., everything works perfectly without issues at least during my experience using them.
The staff support could have been better but they do listen if something goes wrong which makes me happy because sometimes things go really right too :). Keep up good work guys!! Nothing specific comes into mind now though maybe just being able to contact customer care more easily might help? As an agency managing multiple hotels/rentals across different countries this tool allows us to see what rooms are available where quickly, even outside working hours.