Must admit I was a bit scared, but it is a delta exam and if you are using the technology on a daily basis then you can't have a lot of surprises. It didn't seem to be a difficult exam to take. Maybe having delivered the ICM 6.5 a few times in my life, had helped. However, I would like to point out several aspects about how I prepared for the exam:
- never forget configuration maximums - I failed one question because I did not read them properly
- it is a delta exam - so what's new is important especially since 6.5 was more like a major release bringing in VMFS6, security features, NFS 4.1 and other goodies. If you don't use the features in your production environment, stand up a nested ESXi and play with them a bit (of course, always read the manual)
- features you don't use in production on day to day basis (let's say VSAN), read the manual
- use a practice mock exam to help you find your weaknesses and study more (this one from Simon Long is pretty cool)
- lastly, if you don't know an answer, start and use your logic and what you know to eliminate the wrong answers. This method may lead to finding the good answer
For all of you thinking about taking the exam, good luck!