Tanya Huff's "Valor" series is pretty good. Lead character Torin Kerr is a strong, well-drawn character, and she's a sergeant rather than an commissioned officer so it might be a different perspective from reading MilSF depicted from the viewpoint of upper ranking commanders.
The books are very plotty and in each one there's a particular problem to solve, as well as being part of some sort of overarching arc involving an alien war. I'd place the writing style for these as mid-way between Bujold and Moon, with a touch of Heinlein thrown in.
I'm not sure the first two are available in e-book format (but DAW's put out a cheap paperback omnibus), but the latest three definitely are, and the 3rd book is where the series starts to get less standalone and it helps to know the background in future books, so it's a pretty decent jumping-on point for newcomers.