Just finished the series. What excellent characters, world building and storytelling. I'm not usually a fan of the 'mars needs women' trope, but the author really makes it work here. The emotion and chemistry get 5 stars. I really found myself liking all the leads very much. Okay, the main female lead in book 3, not so much, but other than that, absolutely. These books are all on Kindle Unlimited! Even if you sign up for one month, it's worth it for 9.99 for these 4 books. That's Cdn dollars, I don't know about other countries. Apparently Willow Danes is a pen name of Ariel Macarran, under which name she has another really good sci-fi fi romance series on KU. Both are recommended.