Whenever I do reviews (only when asked), I always point out the bad and the good parts, like what you've said here. I wanted to help, not to beat a fellow author with the 'I'm better than you' bat. I also try to give practical solutions to the problems I cited, though mostly based on my experiences, rather than what is in 'theory'.
Oh yeah, and I drop the bad points early on, then the good points, so we end up in high note.
