I bought the complete Peterson extractor set like 3 months ago and have been trying out the different tools it comes with for extraction jobs and I wanted to wait till I actually used every tool in the kit in the field before I wrote a short review on it and I have to say that I am impressed.
Compared to the spiral extractor the Peterson set is much easier to use on the really tough extraction job like a broken key in a ignition where the tumblers in the front is keeping the key trapped inside. Comes with three different scissor type tools that do a good job of pushing aside the wafers and gripping and pulling the key out of the lock.
And I was totally blown away by their sidewinder extractor. I ran a job a few days ago where the customer broke the key in a mortise lock and the key was sunk into the keyway a bit making the use of the regular hook/barb or spiral extractor a toughy. So I gave the sidewinder a try. I slipped it in along side the key and pushed it in gently as far as it would go, then pull the tool back out and the broken key came right out without hesitation or putting up a fight. Just an amazing tool.
If you have trouble using the spiral extractor for any reason I highly recommend trying out the Peterson set. It made my life so much easier.