Wire keycap puller. It doesn't bruise the sides of my keys and I can remove longer unit keys.
I also think you're using the wire puller incorrectly. You're supposed to place the wires at a 45 degree angle so it latches onto the keycap corners, not along the whole keycap.
Like this:
Show Image
Photo from BlueBar, http://geekhack.org/index.php?topic=46376.0
Ohhhhhhhhhhhhhh. That makes a lot more sense now! Oops.
Also, I think the plastic ring pull one is easier to pull long ones out. Although I would love to see someone make a puller to get an ISO return key out without touching any others.
If you have one puller, ring is good for spacebars and the like. But what I do is for the spacebar, I take two paperclips, bend into a rectangle, and use those. Much better.
Ring scratches the caps, its really obvious in painted caps. Wire is smooth, and when you get used to it, its faster. Down, twist, up, knock out. Sometimes you don't even need to knock out until you have 2 or 3 on there.
With rings, its push down, click, up(sometimes doesn't stick correctly) then pop out, and repeat.
