I don't want to split without my 4 way. On the right sized wood, it splits 3x as fast. If you have a log you want in 4 pieces, you run it through once and you're done. With a single wedge, this takes 3 strokes of the ram to get you your 4 pieces. Now how much wood is actually that size varies from person to person. I find many of my logs get split into 6-8 pieces. For the 6 piece logs, I slide the log to my side of the wedge and hit it so the 2 pieces away from me are the right size. I then just slide the remaining chunk back to the ram and push it through centered as best I can 1 time. 2 strokes and I have 6 pieces of wood. As Fred mentioned, gum is too nasty for the 4 way and it's really just a pain in the arse type of wood to split. I would be hesitant to even let someone drop it off next to my splitter for free. For knotty pieces and crotches, I just slip the 4 way off.
I run and Iron and Oak and love their 4 way design. I have seen some others that can't compare.