Here is what works for me... Your butt will thank you for it - especially on those 6-7 hour marathons.
The non-slip rubber backing actually works - it doesn't move- even after a day's excursion... The cushion is ultra comfortable - the difference is day and night... no pressure points.
I was worried about the cells getting filled with water (even if this is rare in the Outfitter) - and making embarrassing noises
(as in whoopee cushion)- and giving new meaning to the expression putt-putting around - but thankfully, no such concern.
The cushion has a zipper. The gel part can be easily removed to air and dry out and the cover is machine washable.
I forgot to mention that the cushion adds only slightly more than an inch in height and even less when seated. It plays a negligible role with the center of gravity issue. However for those kayaks prone to water in the cockpit, I would suspect it would probably keep you drier.
Also turns those punishing stadium seats into an LA-Z-Boy - well, maybe a slight exaggeration. Canadian Tire 10$ on sale, 39$ regular. Highly recommended.