I'd say mechancially the calss is a bit weak. It is though really easy to get into. It seems to be a good story based class as there are some really cool plots and ways to make the character role play and get depth of personally even more here. Sorcous Knack though with the right spell can really be powerful, but you need a high charsima and a dragon with a good spell list to get something worth while. Most of the abilities are passive like the natural armor and resistance, so it is not a class that has a lot of cool abilities.
In the ned it really depends on the type of campaign you ar ein. A more combat oriented one I think would find this class lacking, but a story and character driving high on the role play game would be well rewarded by the options and dragon ally this class provides.