The fork type are naff in my experience. I've got one in the garage that's bent to b*ggery from the last time it failed to separate a ball joint. Good paperweight.
I've never used the scissor type. Why are mini ball joints so hard to separate anyway? They're only little. A good tap on the arm and some heat has always worked on all sorts of cars for me, with much bigger bits.
I have had the opposite experience, I had a stuck ball joint that the scissor type wouldn't budge not matter what I did. Brought one of the "pickle forks" and got the job done (does ruin the rubber dust cover mind you, so wouldn't recommend if you are planning to re-use).