Oh yes, I enjoyed "Old Man's War"; and it does make sense to compare the series to Heinlein. I got about half way through "Ghost Brigade" and then I hit a spell when I didn't feel like military SF, so it's sitting there half-read. I should get back to it... at some point.

Right now I'm reading the second volume in the "Chaos Chronicles" by Jeffrey A. Carver. Interesting ideas and worldbuilding, average characters, and a peril-filled plot.

The idea... is great, but the writing is dull and pedestrian and I had no interest in what happened to the characters
Don't read anything by Alan Dean Foster, then.