I did it twice in my first 10 weeks on the site. I was exhausted both times, but it helped me build an inventory of hubs, greatly increased followers and daily traffic, and because I did it with a group of other writers, I made wonderful friends.
I also learned to generate ideas for topics, and I learned what gets traffic and what doesn't. So it was a nice tool for getting familiar with what works well on the site. If you experiment with the different capsules and how to do things, doing the challenge builds your publishing skills (related to the site's content management software). You become faster at figuring out how to do things for layout.
The downside is that you can start to grasp for just anything to keep up the goal, and end up publishing hubs that aren't up to the quality you'd prefer, or go outside the topics you want to stick to. I've never had a hub pulled for anything, but I know some who have had problems during the challenges and end up spending considerable time fixing them, all because they were pushing for the goal of quantity rather than quality.
The 30/30 is hard, even for an experienced and productive writer. For someone not used to turning out story after story, I'd suggest starting with 10 hubs in 30 days, or 15 in 30. That's still a fast pace, especially if you work, are in school, have kids, etc. But at the end of the 30 days, you'll have products to be proud of, and a good feel for whether you'd like to go for 30/30.