Originally Posted by GoSharks
Mea culpa...saw OP talking about a 'Kindle' and forgot I was in the Fire subforum.
Though I have to admit I had so much trouble trying to get Aldiko to work for me I just continued with my "improved" Calibre. This also made so I only had to deal with one format across my multiple Kindles.
I just use the overdrive app. It works fine for me. I know most prefer Aldiko. I've used Mantano in the past but I can no longer recommend it due to how buggy and bloated it's become.