I've been a member of ITPro.tv since early 2014. During that time I've used their courses to pass multiple CCNA tracks, as well as MCSA and MCSE Server 2012.
Most recently I passed the PMP certification using their 36 hour long video course, almost exclusively. The consensus over at www.reddit.com/r/pmp is that RIta Mulcahy's PMP Exam Prep book is a most for passing the exam. I tried multiple times to study with this book and kept finding myself putting it down. I decided to go for broke and switch over to ITPro.tv. Don and Ronnie really did a great job breaking down the entire exam and relating it to real-world scenarios, even going so far as to mock up a fake project to build an arcade cabinet for their office. The last eight or nine videos in the series are thorough walk-through's of the most common formulas and how to apply them, as well as calculating things like lag time, free float, etc.
I can't recommend their services highly enough.