Hey guys!
Just finished the SANS504 course today, obtained my SEC504 CTF coin and thought that I might give a little review!
The course is structured really well, with a focus on IR on the first day, followed by hacker techniques and tools (and how to look out for them) on our networks.
It really reinforces that in order to be an efficient incident handler, you really need to know:
1) What you're up against,
2) What's "normal" in your environment
Without the above knowledge, you're just going to be spending a lot of time doing guesswork; which isn't what you want to do during an incident when the spotlight is on you.
My instructors were the combo of Kevin Fiscus and Steve Anson, and they were both really great and engaging instructors.
It's an awesome course, and I personally felt there were 3 things that really helped me understand the course materials better:
1) Material from ElearnSecurity's eJPT, which covered general pentesting tools and concepts
2) 
Incident Response & Computer Forensics, Third by Jason T. LuttgensIncident Response & Computer Forensics, Third by Jason T. LuttgensThe book: Incident Response & Computer Forensics Third Edition
3) 2-3 years of working experience
Without the above 3, you can still go through the course, but you'll appreciate the material much better, and you'll find the class pretty manageable.
If you're taking up a SANS course for the first time in your life, please note that you really need to prepare yourself mentally and physically, as SANS courses come jam packed with talks and NetWars. You likely will not have time for dinner, and the pre-talk/NetWars snacks that the training location provide may not be very nutritious or filling.
I participated in the Cyber Defense NetWars as well and got up to level 3 (out of 4).
Although it was an individual competition, I teamed up with a classmate and we hit the challenges together.
The key takeaway is that you absolutely need to know a lot. You'll be tested on your Windows knowledge, Linux kung fu and packet reading skills.
Although we were initially leading in the top 10, we eventually dribbled down to the 22nd place as the both of us were really weak in packet reading.
All in all though, it was good fun and we identified our weak areas!