Wicked Fantasy Factory was Goodman Games attempt to crank your D&D game up to 11. These were the selling points:
- E-Z stat blocks, formatted to put the important combat statistics at your fingertips
- Finishing moves, with rules to make characters more heroic
- Mooks and big bosses, with rules to make combat more dramatic
- Over-the-top action, for adventures that don't slow down!
As you can see from the cover art, A Fistful of Zinjas is a different beast entirely. Unlike the others, it's statted out for 4E. The book and adventure has an extremely anime-esque style. If that's what you're looking for in your game, I recommend it, but personally I preferred the style of 0-3.
I'm currently running a modified version of Arm-Ripper for my 5E group. It's been really easy to convert. I think adventures 0-3 would be a great way to kick off a campaign. These adventures are relatively inexpensive and if you're looking for something a little different, give them a shot.