I just passed the 200-105. It was a pretty difficult exam. I previously passed the ICND1 version 100-101 so now I'm CCNA R&S cetified.
I mainly used Odom's Cisco Press book to study. Although it was a great read, there was some material and terms in the certification that I had never heard of before. So if you're planning on taking the 200-105 please make sure you use as many different sources of material as you can lay your hands on.
I also used Packet Tracer and GNS3. I mainly used CPT. As I read the book I made sure I labbed EVERYTHING!! That is the key to passing! It's one thing reading about it and other to actually configure and troubleshoot any problems. I recommend GNS3 for things that CPT can't do (i.e. MLPPP and PPPoE).
Ok, that's it from me. On to my next cert. I'm thinking maybe CCNA Security or CCNP R&S. Good luck to all!
Certs: CCNA: R&S, CCNA: Sec, MCSA: Server 2012, Security+, A+