This came up a couple of times over the last few weeks, including tonight in Allen's chat.
Somebody asked, "which can you kill screen faster - Donkey Kong or Junior?"
My feeling, based on my recent experience with both games, is that DK was slightly faster, and a run-through of Junior would come in about 15 minutes longer.
Ben said that you could get through Junior in 1 hour 15 minutes. That did not sound right to me. My failscreen run a couple months ago that ended one key short was just under 2 hours, and I was pretty much just running.
A DK game with just top hammers is generally around 1:45.
So, I just tested to see who was right.
I loaded an L5+ level and tore through it as quickly as I could. I got 3:45 (I'm sure it could be done faster by better players). But let's keep it simple and realistic (correcting for rough chain boards) and say 4 minutes per level.
Then I ran through L1 through L4. Looks like that will usually come in at 12-15 minutes.
So, 12 minutes, plus 4x17 = 80 minutes total. Ben was right - it can be done in 1 hour and 20 minutes, and definitely less if you're REALLY pushing it.
Vincent's kill screen speedrun of DK was almost exactly the same time (81 minutes).
My error was taking for granted how much point pressing I was actually doing in Junior. It would appear that even "casual" fruit drop setups really start to add up over the course of a game, without even doing much (or any) hideout leeching. 10 seconds here, 30 seconds here once or twice per screen over 85 screens will catch up with you.
So there you go: at their board-running bare essence it looks like DK and Junior are almost identical in terms of time. Beyond that, your mileage will vary...