I can’t say I ever really felt like the suspension cost me anything meaningful. And it also wasn’t “weird.” And maybe I shouldn’t have been surprised, but I actually was pretty pleased with how it smoothed out really crappy pavement. I had it setup most of the time with 700C x 44mm Compass (now Rene Herse) Snoqualmie Pass Ultralights, which are basically giant slicks. The ultralights are not ideal for off-road - the sidewalls are fairly thin - but they are superlative for “mixed road” or gravel-that’s-literally-gravel. They roll (Crr-wise) about as fast as GP4000s. And with that setup, I did lots of long rides (5-7hrs) on all kinds of mixed fireroad-and-asphalt. It was amazing. I could essentially ride any “flat” surface in the LA area, which allowed me to connect together all kinds of routes that would have been not great on either a pure-road bike or a pure-offroad bike. Basically, it was super for what “gravel” originally meant.
On super smooth, well paved roads, I’m sure you’re giving up a bit of speed. But if you don’t stand much (I don’t), even on good roads you won’t really notice the suspension. And it’s nicer than you might think for crappy pavement.