Just finished Mastiff. While the series as a whole wasn't my favorite (Protector of the Small still reigns there), this was definitely the best book of the set. The ending annoyed me a little but on the whole I quite enjoyed it.
Overall I still rate it Keladry > Aly > Alanna > Beka > Daine.
(Looks like Numair back story is up next. That should be interesting.)