I will say, however, that "bookending" the series and simply seeing how it started and how it ended allows for a good bit of comparisons and insight into how the series changed over the series.
First, one thing that was extremely obvious in The Legend Begins was just how much of the video was re-used, re-hashed video. Every episode featured the Voltron Force rushing out to their lions and every episode featured the animation of the lions forming Voltron. There were several shots that seemed to be, essentially, "stock footage;" it was animation made for the show, but was re-used - not only in multiple episodes - but, sometimes, multiple times, back to back, with mirroring techniques to flip the image and use it again. The episodes in Voltron: The Final Battle don't have anywhere near as much re-used animation, and what is re-used (and mirrored) is done in less noticeable ways. In these final eight episodes, you rarely have to watch the animation of the Voltron Force going to their lions and there were a couple of stories that spanned more than one episode and didn't feature the animation of the lions forming Voltron at all, if I recall correctly.
Secondly, the Voltron Force (and, hence, Voltron) seems to have gotten a bit smarter. Perhaps it was a result of thousands of children yelling at their televisions in unison, but toward the end, Voltron actually forms his Blazing Sword first and asks questions later. There seemed to be fewer instances that made me want to yell suggestions at the screen; the Voltron Force seemed to have the knack of things, by this point.
The eight episodes included in The Final Battle are eventful, indeed. For starters, there is the reappearance of Sven, one of the original members of the Voltron Force who was replaced by Princess Allura. The power struggle between King Zarkon and his son, Prince Lotor comes to a head, resulting in Lotor taking the throne and Zarkon becoming a Robeast. Coran's long-lost son returns to him... or does he? The season ends with Voltron, the Galaxy Garrison and even the Castle of Lions, itself, working together to put an end to the newly Kinged Lotor and take back "Planet Doom" from the grips of the Drule Empire. At the very end, Pidge sends an email to his brother, which gives the American audience their first glimpse of the vehicle Voltron Force, which was the focus of the second season, here.
I was surprised to see how light the special features were. There are exactly two, one that is little more than an advertisement for the new Voltron Force animated series and the other an advertisement introducing a new poseable action figure of Voltron that includes a "Blazing Sword" - a version of the sword which has angular plastic star-bursts coming from it, giving it the appearance that it is "blazing." I noticed the toy also includes a normal version of the sword, as well.
If you watched Voltron in your youth and, like me, you never saw the end of the Five Lions Voltron, I highly recommend picking it up. It was nice to see how everything resolved in the end. I wasn't really expecting things to have resolved; I had assumed it went on with the typical Voltron formula until it was cancelled. Also, I never really watched the vehicle Voltron Force, and hadn't realized that one had lead directly into the next.