Reviewing 'Echoes of Betrayal' and 'Limits of Power' together, because I read them back-to-back, and there isn't any radical distinction between them.
Both books are very middle-y. Not really middling, just middle-of-series-y. You're expected to know the characters already (that's OK, because I do), and to be invested enough in their ongoing drama that you're not expecting each book to be it's own individual story with clear rising-action-falling-action-conclusion plotting - they're not - but that's (mostly) OK. This series really does have enough engaging characters and interesting scenarios that I'm fine with just following all the characters around and seeing what happens next. It's good entertainment.
The content - well crafted, but fairly typical fantasy fare - kingdom-shaking issues regarding magic, royal marriages, human-elf interaction, evil wizards, dragons... all that good stuff.
I love Moon's strong female characters, and her realistic portrayals of warrior/military women.
The one small thing that annoyed me was how much everyone talks about Paksenarrion - with all that talk, I feel like she should've made more of an appearance.
I'd recommend this series to anyone who's looking for a nice, solid, but non-genre-bending fantasy series with a large number of pages to get lost in - but I'd recommend starting at the beginning.