I personally find the Blu-ray discs totally worth it. If you have a good sized HDTV and value seeing all the detail they extracted from the original 35mm film the Blu-ray sets are worth it, if you can find them for a good price.
The other plus depending on how you feel about the 2006 CG stuff is that the Blu-ray sets have the original visual effects included and can be toggled back and forth with the updated versions.
Otherwise, the DVDs are very good and of course are from the same masters so they have the same excellent color saturation, etc. from the remastering.