Comfort: very comfortable. Great for walking 18 or 36. Cushion feels close to adidas ultraboost but a little firmer. Feels slose to a FJ Quantum.
Fit/sizing: I have gone a full size up. Usually I am a size 8US mens in footjoy, 9US with adidas and nike running/basketball sneakers. Since the heel cup is soft, there will be heel slippage even if you use all the lace loops.
Stability: Same as any other spikeless shoes - great if dry, not so great when wet.
Would recommend if you want a comfy all day, multi use sneaker. But if i had a choice, i would go with the FJ Quantum instead for a better fit.