In practically every way, the new iteration of Battlestar Galactica has taken the core elements of the original series and improved upon them. Not only is the scope of the new series much grander, and the execution of it more technically polished, but more time has been spent on deconstructing what a science fiction series normally delivers and has expanded it into something much more universally significant.
Not that science fiction isn't often significant — as our culture is rife with its lessons and examples — but it's often very narrow in its message or appeal. Creators Ron Moore and David Eick kept the best parts of that tradition and then added more, making a series with a rich history, mission, and peoples... that just happens to be set in space. It contains action, drama, humor, philosophy, romance, political overtones, moral ambiguity, religious tension, and technology run amok. It's not a perfect series, but it often comes dangerously close.
The Blu-ray release of season 4.5 is the first for the series - along with the recently released Complete Series - to be released in high definition, which is odd since the series was filmed specifically with high-def in mind. But the breakneck speed and tumultuous tension of these final episodes show off the series admirably.
To call this a half-season is understating its importance, as ultimately it's more of a practical distinction. These ten episodes (or eleven "parts") came after the extended break caused by the writers' strike in '07-'08. Add to that it following an expansive mid-season finale, 4.5 becomes more like a mini season on its own.
The action begins with the humans and Cylons discovering Earth, only to find that it is an uninhabitable wasteland. With their dreams all but crushed, the remaining survivors begin factioning off into splinter groups, the tension between Cylon camps escalates, and the hopes of survival for either race seem to rest with the human-Cylon hybrid child, Hera. In short, things are going to get a lot worse before they get any better.
Without beginning a debate on the finer points of Battlestar lore, I will simply say that my personal opinion of the series finale, "Daybreak", was overwhelmingly positive. The modern day tack at the end was a little corny, but other than that the creators did an excellent job of wrapping up what had become a very complicated and emotionally draining journey. Loose ends were tied, obstacles were overcome - although some in a rather anti-climactic fashion - and the outro for our characters was not rushed at all, making it a very satisfying close. Series endings can often be rushed and sloppy, as corporate axes quickly hack under-performing shows. Battlestar Galactica was in the enviable position of being a rather successful show that was able to bow out on its own schedule, when the story had been told to the tellers' satisfaction.