I found this cross-series collection of novels all dealing with the same enemy but in different ways, in different times and sections of space to be an interesting concept. The separate novels were entertaining and fairly well-written for this type of novel.
This will be a bit spoilery, especially if you haven't read Star Trek: Destiny (which, if you haven't, you really must read!).
Plot details: The Voyager fleet split off into different directions in the previous novel (Unworthy). While Voyager was dealing with the Indign, a few of the other ships were investigating the Children of the Storm, a race of telepathic, telekinetic space spheres that destroyed an entire Borg fleet when Captain Dax took the Aventine to the Delta Quadrant in Destiny. Voyager finishes its Indign mission and finds that the Children of the Storm part of the fleet hasn't been heard from... uh-oh! From there it's a race against time as the good guys try not to die at the hands of these Children while at the same time upholding Federation principles of non-violent exploration (to the extent that it's possible, anyway).
Verdict: This one has an interesting premise, which is part Voyager (strange enemy was invulnerable to the Borg!) and part Original Series (the aliens are very alien and the story is driven by a desire to learn and communicate rather than destroy, using a combination of Federation empathy and Trekky science). So, it's on the good side as far as Trek plots go. The characters here are interesting too. While Unworthy focused primarily on the usual heroes of the Voyager story-line, this one is populated with characters on a few of the other ships in the fleet. I was expecting this kind of character diversity ever since the Voyager fleet got together for the purpose of exploring the Delta Quadrant, but it's here for the first time that it actually happens. The captain and the doctor (both old dogs) of the Esquiline have some good moments, but the most compelling parts of the novel take place on the Demeter, with its mutinous contention between the commanding officer (a real galaxy-class biologist) and the XO assigned to keep an eye on him. While tensions rise on board the ship, the Children of the Storm have them under siege. Some want an all-out fight for survival while the more enlightened commander wants to find a scientific/diplomatic solution. He's no Picard, but his solution is elegant and very much in the spirit of the best of Star Trek.
Despite some clumsy writing here and there, the character-development and good old-fashioned Trek plot make Children of the Storm a pretty good read, even if you're not a big Voyager fan.
Next up: after two or three non-Trek books, I'll read the brand-new TOS trilogy (Legacies), which should be complete and in bookstores by the end of August!
This one picks up where Full Circle left off. This isn't very spoilery: Voyager returns to the Delta Quadrant (this time, with the "Full Circle" fleet) for a new mission of exploration, and a lot of our characters are back, albeit most in different roles.
I liked this one better than Full Circle mostly because the Warriors of Gre'thor story (which I was dumped into, in medias res, in the previous novel) did not play a role besides a brief mention. The story is indeed far more coherent in Unworthy. Everything revolves around the discovery of a new species with a mysterious connection to the Borg, and all the ongoing character arcs intersect nicely with this plot and advance satisfyingly as a result of the plot. What's more, the plot has a beginning, middle, and end all in one novel! (Yes, this is the kind of thing worthy of note in our present age of trilogies, quadrilogies, decalogies, and so on). In short, Unworthy occupies a good middle-ground between tying in with the rest of the post-TV Voyager book series and being a stand-alone story that can be enjoyed by someone unfamiliar or only vaguely familiar with the happenings of the Voyager crew after the TV series ended.
As far as character arcs go, they're all pretty good here (if you read my review of Full Circle, you'll see that this is not the case with that novel). The best, in my opinion, is Seven's arc -- she's struggling with an identity crisis that goes beyond that found in the TV series, and we really see some character development here, enough that I'm curious to see how she develops in future Voyager novels. Chakotay, Tom, B'Elanna, and Harry get a lot of page time in this one, and Reg Barclay even gets a few exciting moments. A guest character from one episode of Voyager shows up too, quite unexpectedly, and I'm not entirely convinced that that part of the plot was necessary... but it was at least interesting.
Overall, it's a pretty good Voyager book, and I recommend it to Voyager fans especially. You will probably enjoy it as a stand-alone, but it's still better to at least read Star Trek: Destiny and Full Circle first.