I've had a few of the previous 26" Scott Sparks, with the Scott Nude shock. That shock made the bike, and I loved it for marathons and stage races. I didn't like the specific DT maintenance that was required though. Stopping 3 times in the CristAlp to use a shock pump at tech services wasn't ideal. But getting a specialist shock service in Europe in summer when you're never really standing still just doesn't happen.
So I went for a 29er HT until the past week, on a Scale 29 Premium (HMX frame). Croc, Cape Epic, Fling, Otway - all good. Kind of harsh at the Cape Epic to be honest. But it was light and agile.
A couple of cracks ended that, so I've picked up a Spark 29 Expert and moved most parts over.
So far it's ok, I'm using it out at the ICME at Alice Springs. The mid range DT shock doesn't feel harsh in the stroke or anything, but I miss being able to ramp up the compression. I'm going to try a RP23 (custom tuned) once back home. Previously, I didn't like those as they lack the full lock out.
The Spark is a basic suspension design, without tricky linkages. I've been happy with it before, so time will tell. I've been stoked with the climbing traction, I just need to find more traction and confidence the rest of the time after too much time on the road recently!