I had a night with a GSO 8" RC and the C8 side by side, and the planetary views were good through the GSO, but clearly better in the C8HD. We went back and forth quite a bit, and the C8 definitely outshined it for Saturn.
Didn't view any other planets with it on the night though, so it isn't much of a sample
I don't have much of a dew problem with my SCTs, I use a l-o-n-g homemade dewshield and don't use heaters and I am usually okay for most of the night.
I modified a hairdryer to run quietly and with less heat and use that for a few seconds on the rare occasions that I still need to de-dew the front plate without waking the neighbours.