I did enjoy them, indeed I did. Not many there. Half a doz kids 12-14 stunting on the open area half way down the first descent you come to after the climb from the car park. Three adults building something on the next trail over, at it the whole time I was there. I saw no more than six other people. Whichever trail I chose, there was never anybody I caught up, or saw, or heard, or was caught up by. Once I'd committed to a trail, it felt like I was the only one there.
Several trails, maybe many I didn't count, appeared to be out of use. I went down a few that were distinguished by the undisturbed pine needle litter at the start, followed by lots of trail debris and the odd fallen tree. I soon learned not to go down the trails that showed no signs of use at the entrance; it wasn't as if there was a shortage of them. Most of the trails I started down split into a choice of trails, sometimes more than once. On some trails that I started down, I was never really sure whether I did the same one more than once, despite trying.
The trails were dry and dusty, but grippy, but I suspect that after rain they would be a nightmare. The surface is just earth sprinkled with decayed pine needles. The trails are fairly steep and with multiple left-right banked turns with tabletops and small drops over roots. There is the occasional heart in the mouth obstacle that you need to spot early enough to make a decision.
The biggest "problem" is that the trails are relatively short most less than 500 yards, some much less. And all end with the need to climb back to the beginning up three (I think) access roads. Ideal for emtbs really!!
The Watchwood carpark is about a mile away, with a long hard surfaced track to climb to get to the trails. It's wide enough for trucks. The A614 is at the bottom of the trails and there are laybys and gateways to park in. I guess that mtbs would prefer to park there.