The judgment upon whether Oliver Twist would have been better off under the employment of Mr. Sowerberry or that of Fagin is qualitative, and, as such, dependent upon the reader's interpretation rather than textual support. For, in neither case is Oliver "well off." It is only after Oliver escapes the clutches of Fagin and lives with Mr. Brownlow that he is "better off."
Under Mr. Sowerberry
1. Oliver is fed dog scraps for food. So hungry is he that Oliver "clutch[es]" at these meager "victuals."
2. He is made to sleep in the room where empty coffins rest. So disconsolate is Oliver that he wishes he were put into a coffin forever,
But his heart was heavy, notwithstanding; and he wished, as he crept into his narrow bed, that that were his coffin, and that he could be lain in a calm and lasting sleep in the churchyard ground, with the tall grass waving gently above his head, and the sound of the old deep bell to soothe him in his sleep.
3. Oliver is subjected to the "ill treatment" of Charlotte, Mrs. Sowerberry, and the brutish Noah Claypole, who is fed better than he, and who taunts him by insulting his poor, dead mother. When Oliver comes at Noah with fury, Charlotte beats him.
Charlotte gave Oliver a blow with all her might: accompanying it with a scream, for the benefit of society.
4. After Nathan reaches Bumble, the charity-boy informs the beadle that Oliver has acted violently; further, he tells Mr. Bumble that Mrs. Sowerberry has asked that he come to beat the boy.
5. Bumble tells Charlotte and Mrs. Sowerberry that Oliver has become mean because he has been fed meat.
6. Oliver is locked in a cellar after being beaten by Mr. Sowerberry and struck by Mr. Bumble's cane and ordered to "his dismal bed."
1. After first arriving, Oliver has shelter and is fed a "share" of sausages and a drink that makes him sleep. Later, he is still fed better than he has been at the Sowerberrys'.
2. The lodgings are filthy and located in a part of London which is very sordid.
3. While living with Fagin and the other boys, Oliver shares with them a dangerous life of criminality, a life which easily could come to an abrupt ending in prison or in being hanged.
As neither way of life is propitious for Oliver, and since Oliver could go to the "ghostly gallows" for stealing as Fagin employs him, it would seem that his position with Sowerberry would have been preferable to the job of pickpocket. On the other hand, if Oliver had not been captured by Fagin and taught thievery, he would not have been taken in by Mr. Brownlow and eventually been discovered to be the child of Brownlow's daughter. With Mr. Brownlow as his grandfather, Oliver is reunited with his real family, and lives happily ever after having again escaped harm from the villainous Dodger, and even death thanks to Nancy. So, in the long run, Oliver Twist is better off for having run away from the Sowerberrys' house.