As promised Wizards officially released the new web-based Adventure Tools yesterday, which specifically meant the new Monster Builder tool (the announcement can be read here). The announcement seemed to include as much text about what the new tool wasn't as opposed to what it was. Regardless, you can find the link to the new tool - and to the still available to be downloaded but never to be updated Adventure Tools - here.
The new Adventure Tool has been available to a limited set of customers for beta testing over the last several months. Wizards was trying to link in the use of the Monster Builder with the new Virtual Table Top tool, so they have essentially been beta testing both simultaneously. With that amount of testing and feedback one would think that the Adventure Tool release yesterday would have been more well received. It was apparently immediately clear that the release was the same beta version with very few if any of the promised features or corrections (read more here). Apparently the tool also had to be taken offline briefly yesterday when a major bug was discovered.
I have avoided accessing the new tool so far. I figure that whenever something new like this was rolled out there would be issues with too many users overloading the servers, but after a few days these things have usually sorted themselves out. I understand that Wizards has been trying to push the envelope of gaming by providing tools and on-line content that all link and work together, but they still appear to have trouble getting the basic building blocks done, much less done well.