I like it and I am going to try running a fantasy game with it.
The system is flexible and seems suitable for many different styles of settings.
The system does involve some table-lookup when using skills and in combat, but personally I like that stuff.
Some things could probably have been a little simplified without loosing playexperience, but overall it looks pretty well balanced.
The card-deck is not for me, but it is optional and if you dont like it you can just skip those parts of the rules.
On the publishers homepage there is also conversion guidelines between Masterbook and OpenD6,
which helps in making a lot of stuff available for use with Masterbook as rulesystem.
One drawback is that the scans are just images. You can not copy text or search for text. That is irritating but not a dealbreaker.
[4 of 5 Stars!]