Penmachno is more natural than CyB. There’s only one trail, a 20km red loop, with an additional red side loop of another 10k or so. It’s primarily singletrack (with fireroad climbs) and is best described as being simultaneously rocky and flowy. Given that the nature of the terrain (and the trail’s conatruction) means that it retails water, it is bound to be wet, especially on the top section before you start the series of fairly dizzying descents back to the carpark.
In effect CyB are at two ends of the spectrum. One is a massive trail centre with all the facilities, the other is a carpark with an honesty box and one trail.
IMHO Penmachno is one of the best trails that I have ridden. It is technically challenging, rocky and fast, with a series of descents at the end that are as good as I have seen. If you can handle your feet getting soaked you’ll be fine as the water is all primarily on rock, so whilst it is certainly wet in places, it is very rarely muddy and gloopy, and you’ll still fly along. That said I wouldn’t bother with the additional loop as it is very pedally and extremely wet in places.
Hope that helps!