I never digged it. But I came from 4chan. At first reddit was like a more controlled 4chan. Since you needed an account it was easier to control the randomness that 4chan can show. But reddit can ban you for stupid reasons and in that sense 4chan is more true. You may see a lot of opinions about a specific topic and they may be manipulated by the mods allowing it or not allowing it at all. 4chan has a boring cesspool for years now. I think reddit compares more to 4chan than digg.