First off, Young Justice is a great animated show airing on Cartoon Network. It is a worthy successor to all the DC animated series that have come before it.
Volume 3 has four episodes (#9-12) from the first season, and features the kids facing Psimon (of the Fearsome Five), Lex Luthor, Ra's al Ghul, Sportsmaster, Cheshire, the villains at Belle Reve Penitentiary, and Red Tornado's "siblings" Red Torpedo and Red Inferno (yes, really!). The kids are also seen in their high school environments with cameo appearances from other DC teens like Mal Duncan and Karen Beecher (from the original Teen Titans), Wendy and Marvin, (yes, THAT Wendy and Marvin, but NO Wonderdog), and Bette Kane and Barbara Gordon. The only Special Feature is a Digital Comic Book reprint of a few pages and panels from Young Justice #0 that you can page through screen by screen. For those of you who don't collect comics, this particular issue takes place just before the end of Episode #2, so it's almost like watching storyboards of deleted scenes. Cool!
And for you folks who support this show and ALREADY have Volumes 1 and 2 on DVD, and only want Volume 3, then purchase this set, instead of Young Justice: Season One - Volumes 1, 2 & 3. That "package" combo set has the EXACT same 3 discs as the individual 3 volumes, with NO additional features. However, If you HAVEN'T bought any individual volumes yet, then by all means, the "package" set is the way to go.
Now for all those newbie collectors of the WB animated series who are all whining and complaining over and over again about Warner's marketing strategy of only releasing a few episodes at a time for a new series, well, this is nothing new! They have been doing it this way for years. This is how they determine how popular a series is, and whether or not to release full season sets. You folks are doing a DISSERVICE to the show by telling folks not to buy them, and you JEOPARDIZE the chance for full season sets.
Would I like to see them start off with just full season sets, or half season sets? Absolutely, who wouldn't? Uh well, the average consumer, that's who. These initial releases are geared toward the general public, and NOT the "I-want-it-all-now-and-I'm-entitled-to-it" fanboy collectors. The casual buyer just wants to sample a show to see if they like it. Not everybody reads comic books and knows these characters, not everyone has Cartoon Network or religiously watches it to find new episodes, and believe it or not, not everyone has TIVO or DVR's.
Just about every WB animated series has been initially released this way in individual volumes. If they sell well, then they will switch to full season sets. This is what happened with Super Friends, Batman: The Animated Series, Superman: The Animated Series, Batman Beyond, Justice League, Teen Titans, The Batman, Batman: The Brave and the Bold, even A Pup Named Scooby-Doo, and What's New, Scooby-Doo?
But, and here's the risk, if they DON'T sell well, they won't even continue the individual volumes OR release a season set. This is what happened to Static Shock, Legion of Super-Heroes, and Shaggy & Scooby-Doo Get a Clue! I'm a completist. I want it all, no matter how bad the show is to watch (I'm looking at you, Shaggy & Scooby...)
So, if you want full season sets of WB animated series, you need to support these individual volume releases, whether you buy them or not. And waiting for a hopeful season set is obviously a great alternative to buying the individual volumes now, and then upgrading later. But, if you continue to whine and complain over and over, and give bottom ratings to great shows, and in turn that influences folks to NOT buy them, which in turn results in low sales, well, then you have no one to blame but yourselves if you are still waiting for your Legion of Super-Heroes season sets. Plain and simple.