Yes it is. This has all the new focus upgrade system and new dungeon content as seen on forgecraft and via various youtubers.
As has been reported in the minecraftforum thread, there are a few bugs in this release. Most of them are relatively minor, but azanor said he will be releasing a followup patch shortly to address them. Make sure to update *ALL* your other thaumcraft add-ons as well. Thaumic Tinkerer, Forbidden Magic and Automagy all apparently have updated releases to work properly with this new version. Since the update has been out less than a day, take the usual precautions. There has been nothing definitive stated on upgrading existing worlds.