I like Neonatology Basic Management, by Gomella, Lange Publishing. Biggest problem with UpToDate is that it, IMHO, is poorly organized, when I used it for medicine I would type in one topic and get several different articles which I would have to read to get the gist of it. UpToDate, I will have to admit, is good for specific management questions for a specific patient, but doesn't help much for reading in depth about a certain medical problem.