I just finished reading one or two posts of every slog (okay, a couple I skimmed). Here are the ones that, for one reason or another, I particularly like: they’re funny, they’re well-designed, they’re informative, they’re well-written, etc.
On the other hand, repeating keywords rules a slog out for me. Not updating in over a month also makes it a non-visit, even if that first and only post was brilliant.
Also, observation: All poor slogs are alike; each good slog is good in its own way.
Hope the list leads you to an enjoyable read!