I too like Grover Pro, and have been using it for a while. It is very feature rich, and easy to use, also looks great and matches the look and feel of many of the stock apps. It can download episodes in the background, and is customizable beyond what the default app is able to do.
Seems to be sucking a lot of battery on the latest insider release (I basically listen to it for 8-10 hours a day, but it is using a lot more of my battery than it used to. I would say 20-30% more). I sent the dev an email about that, hope he can address it. He is also generally very responsive to feedback and help.