I had the pleasure of attending a 5 day SQL Server 2012 Internals and Query Tuning class led by Kalen Delaney the week before last. I had a head start going into the class because I had already read SQL Server 2008 Internals (http://www.amazon.com/Microsoft-SQL-Server-2008-Internals/dp/0735626243) cover to cover and have been working with SQL Server as both a developer and DBA since version 7. That said, while much of the class-content further reinforced the knowledge learned from reading her books, her blogs and on the job experience, I still picked up a ton of valuable tips about SQL Server internals concepts, DMOs, system stored procedures, execution plans, the Optimizer and even SSMS via the demos. Kalen is an amazing teacher and presenter and a genuinely nice person.
I would encourage anyone serious about SQL Server to do some in-person training as a component of your training and further education efforts. I cannot articulate how nice it was to be able to ask detailed questions to someone who has authored books on the topic and have a dialogue until the details made sense. Not all trainers or training will be as great as Kalen’s was so do your research and be sure you’re spending your training dollars as wisely as possible.