If you want to compare Borg creation/destruction tales, I don't think the Destriny trilogy is nearly as good as The Return. Having said that, I haven't read Shatner's book in 10 years, so my judgement may have changed.
I remember liking Shat's The Return when it first came out but IMO, it's not even in the same realm as David Mack's Destiny trilogy. Destiny is arguably the best executed "event" we've seen in treklit history. The ramifications of this storyline will (hopefully) be felt throughout the 24th century trek books for years and years to come. It was a game changer.
I just gotta add that if Kirk's resurrection had been embraced by the main line of 24th century books and not just the books by Shatner, then that (his resurrection) may have been the game changer of all game changers...at the time anyway.