The book opened very interestingly: by giving the readers the same stream-of-conscious thoughts as the first (smoker) character, it draws the readers in and makes us sympathetic with his mother (much more sympathetic than we otherwise would have been).
I found Mr. Grewgious similar to Mr. Lorry from A Tale of Two Cities. He insists on being an "Angular" man (comparable to being "a man of business") although he apparently harbors kindly emotions towards Rosa. 
Although initially I disliked him, Mr. Crispackle's character improved upon further acquaintance.