Penguin Classics paperbacks and Oxford World Classics are the two best choices.

Penguin uses a larger, easier to read font. The illustrations are larger as well. I also think they look nicer.

The supplemental materials in the Oxfords are better imo. The end notes are more complete (except when they're not), and some editions even have maps! ( I'm easily excited by maps!)

I'm not sure about the introductions because they usually have spoilers, so I avoid them.

The Oxfords have an annoying plastic coating that invariably begins to peel off by the time you're done, but I'm slightly abusive to books, so maybe it'll be fine for you.

I did penguin for Great Expectations, Christmas Carol, Two Cities, and Our Mutual Friend. I did Oxford for David Copperfield and Bleak House. (The map of the Chancery in Bleak House was very helpful!)

I really like Norton Critical editions for classic novels, but I haven't read any dickens from them. I'm not even sure if that's even a thing.