I don't own it, but I've rented it. If you're a fan of the show and you collect DVDs, it's a must-have.
The primary bonus is getting to see the shows unedited (unlike how they've aired on CN), and you get the option of English or Japanese (with subtitles) dialog, and the performances by the original Japanese cast are quite superior to those of the English dub. IMO, out of the English cast, only Melissa Charles (Ed) and Wendee Lee (Faye Valentine) do justice to the performances by the original actors, but Wendee's still pales to Megumi Hayashibara incredibly-sexy Faye.
The set is kinda light on extra features (comparing to other DVD box sets), but it's a pretty nice total package, IMO.