I have both a Sonor Giant Step Middle pedal and an Offset pedal. The Sonor pedal isn't being made anymore and it was VERY expensive. I was a Sonor dealer which is why I have one and it's now 19 years old and still my main pedal.
I bought the Offset (chain) pedal as a backup and have used on a kit in my studio. My first impressions - the drive shafts were too short for how I like to set-up the kit. They do sell longer ones but want like $65 each for their longer ones. I purchased an $8 DP shaft sleave and cut it down and made the stock shafts longer. That solved my set-up issue. I next found that the springs on the middle section were two stiff for my playing so I swapped them out for standard Gibraltar springs. I then find the pedal very stable and responsive.
Middle pedals are not for everyone, their purpose is to allow you to be centered and get the kit tight. Your best bet is to find a shop that has one and try it out.
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