Personally, for anything except comedy I like to read moderately-long bursts rather than short snippets--when I follow works that update daily but have updates that are too small I often stop reading for a while on the assumption that when I start again later I'll have a juicy backlog to trawl through. (Part of me wonders if it's just a matter of how good the author is at finding good stopping points though). HPMOR updates are not that small, but with its plot-heaviness I think I still found that I enjoyed it better when I read entire arcs at once than when I read chapters as they came out. I even considered not reading chapters once or twice until the next existed.

Of course, individual chapters are healthier for my sleep schedule...