I'm a huge Picard fan but I can't say that Cristobal Rios was my favorite character of the series. I felt he was just too similar to so many other tramp freighter captains I've seen over the course of my decades of science fiction fandom. JJM smartly plays into this with the fact that the story has Raffi Musiker arrange for him to become one while ignoring the fact that Rios doesn't want to be. He doesn't find it to be a romantic, exciting, or entertaining pulpy adventure as seemingly everyone else does. It makes a nice difference from Han Solo and Malcolm Reynolds even as the story does become a romantic exciting entertaining adventure.
The premise is that Rios has just been kicked out of Starfleet for the crimes of his supervisor and he's lost all of his friends but one. Raffi decides to set him up with a tramp freighter and the life of a Han Solo-esque rogue but this proves to be significantly less glamorous than the movies show. I also got a huge kick out of finding out that JJM was going to make extensive use of the Iotians from "A Piece of the Action" with them being Rios' version of Jabba the Hutt. Still gangsters after a century of contact with the Federation, they are both ridiculous as well as very good at thriving in a galaxy that has largely forgotten how to deal with criminals.
Part of the book's fun is how miserable Rios is dealing with the loss of his Starfleet career, how disordered life is on a tramp freighter, and how angry he is about Starfleet's betrayal vs. the fact that he is going on a series of increasingly wild treasure hunts. Rios is a terrible businessman, fitting from an Earth Hu-Mon (to quote the Ferengi) and probably would have just given away his ship in a weak if not for new character, Ledger, forcing him to pay a debt that is obviously meant to never be repaid.
JJM's experience in Star Wars clearly shows as he makes the transition a bit better than other writers might. It reminds me of the old Brian Daley Han Solo novels that I felt were the best of the Star Wars Expanded Universe. JJM envisions a seedy underbelly for the galaxy that has always been there (Harry Mudd anyone?) but has never been given particularly much attention. I also appreciated the return of a TNG villain that was underused too and won't spoil the surprise of. I will say it was kind of amusing to note that this book brought them back just as they used as an inspiration for Lower Decks too.
While I rarely comment on this element, I also give the book's handling of romance props. Rios is a very dashing protagonist who manages to handle relationships with no less than three women in the book but somehow doesn't come off as skeezy over it. I also appreciated that one of them is with a significantly older woman and it's not treated as the least bit weird. I actually regretted that at least one couldn't continue because, of course, he's alone at the start of Star Trek: Picard. I also regret we'll likely never see any more of the Klingon merchant lord Verengar--unless we get a sequel series to this!
So, top marks and people should really buy this! Some of the funniest most entertaining Star Trek fiction I've read in years and I've read over a hundred Star Trek novels. Hell, probably closer to two hundred. I have maybe a few minor complaints that are almost insignificant to mention like some of the goons getting away with their crimes when I felt a more final fate would have been better but forget it, Rios, it's Iotia. It's still a very solid and fun book that makes me like the Rios character a lot more.