I used in my personal site, and I am going to extend to other sites I manage. Easy to install and setup. Very good and clear documentation. I forgot my key and, following the instructions, recovered easily the access to my site.
I installed Admin Tools in all the sites. Easy and comprensive interface, easy updating. Basic free usage, with the possibility to upgrade the level of service with the payed version. Good and clean documentation. I have not run into any problem with it.