I use it every month and I have thrown 200 pushes at a new site in 30 days. so yeah it is effective.
Besides all that, there are some very good improvements coming soon. I don't know what exactly but knowing Greg and Kevin it will be good.
Linkpushing was great for me. BTB and company have done a great job with it.
I often tier the results with my own solutions (wikis, web 2.0s, scrapebox, forums, social bookmarking, etc) to give it more juice. I used mine on fairly new domains.