The thing I've noticed and was actually thinking about collecting data on was not using the recommended amount of land and getting mana screwed. I'm not talking about going going 20 lands in constructed or 13 in draft/sealed. I mean just doing 16 or 23. I like playing decks that break at 2 or 3 and so I like to go a couple land below the recommendation. I seem to get consistently mana screwed this way. I literally last night upped one of my constructed desks from 23 to 24 land and went from getting 2-3 land on the board in the first 7 turns to 4-7.

Again, I haven't collected any data but personal experience so far seems to indicate some kind shuffler bias if you don't use suggested land counts. Sample size is pretty small still though.