Having just done this job last weekend, and for whatever it's worth, this tool:
http://www.amazon.com/automotive/dp/B0015PN010works positively fantastically for separating the ball joints from the steering knuckle. The only gotchas are:
1. Upper ball joint: You need to jack up the control arms so the upper arm is about level to gain adequate clearance to insert the tool.
2. Lower ball joint: You need to remove the brake caliper bracket (expected) and then turn the steering knuckle fully inboard to gain clearance to insert the tool. As I was replacing everything up there, I first popped off the steering tie rod, which made it easy to turn the knuckle.
I bought the full OTC ball joint service kit (http://www.amazon.com/OTC-6295-Front-End-Service/dp/B0002SRH7O/ref=sr_1_1?s=automotive&ie=UTF8&qid=1373526904&sr=1-1&keywords=OTC+6295) a long time ago, but that #6297 is the tool I use 10:1. It's *much* easier than a pickle fork, and it doesn't mangle ball joints, so you can use them again (if replacement isn't the goal, obviously
). If you're just replacing ball joints, using this tool instead of a pickle fork means your steering tie rod ends aren't at risk. Plus, you get a nice, satisfying POP when the ball joint comes out. My dog is terrified every time she sees me with it.