I’ve had the same issue for a client. Zookoda looked awesome, but was in the midst of becoming unsupported. I tested for two weeks, and was glad I did, because while the first week was great, the second week the emails were sporadic, and then support was non-existent. After that, I’ve been giving FeedBlitz a try. I don’t like the interface that much, but its been okay. I’ve been planning on using the expanded functions under FeedBurner to give that more of a go. My biggest concern is that the user doesn’t receive too many messages per day, so grouping daily changes into a single email or being able to set some count—if four new posts today, send is my primary concern.
It really is too bad about Zookoda, because their services and ease of use were pretty awesome.