How are Hastings and sheppard similar and different ?

Sheppard becomes Poirot's assistant like Hastings was. THey are more similar than different. Sheppard however seems intelligent, a trait that Hastings lacked. Hastings had imagination which Sheppard didn't have. I don't think that Sheppard had the same loyalty to Poirot that Hastings had. They both work well with Poirot in their own ways.