Here are my commentary recommendations for I and II Samuel, to be updated as I discover more:
Francesca Aran Murphy’s Brazos commentary is a fun romp through I Sam that does almost no close textual work, and the historical background stuff she does is really, really reckless. There’s some Balthasar and Augustine powering her engine, and she seems most interested in constructing an anti-modern political theology from I Sam. It’s really great.
Hertzberg (OTL) is a really great mid-twentieth century German theological commentary. Among other things, it is heartening to realize that solid theological interpretation of scripture was going strong earlier in the twentieth century before it fell back into vogue around the turn of the century.
I have not read it, but my friend Andy Kadzban tells me that Peter Leithart’s A Son to Me is a really great theological reading of Samuel. I’m pretty sure it’s a short and inexpensive book.
Robert Alter’s translation of the David narrative (The David Story) is very interesting. He tries to translate I & II Sam as a piece of world literature, where dense literary weavings are his primary concern. His overtly atheistic and demythologized reading gets depressing after a while, though.
historical/critical/modern eat-your-vegetables commentaries
As you can see, I have not been able to find a good historical-critical commentary on Samuel, but there seems to be an abundance of good theological commentaries on it. There are far worse problems, to have, for sure…