My backyard and where I rode my first mountain bike 20 odd years ago. There are loads of better routes than the ones listed on those websites, I have never come across a website showing them though. Have a look on OS maps, a lot of the tracks are shown on there by black dotted tracks. Some really good singletrack and some steep downhill sections. (You can use bing maps to look at OS maps)
It is very muddy at the moment and was quite icey with snow patches this weekend. As poster said above, your learn to love the mud. I have had many laughs trying to get through huge puddles and streams only to come off and be covered in mud and sheep shit.
Much more fun than most of the North Wales trail centers. Also check out routes around the Horseshoe Pass, Clocaenog and Berwyns