Man made trails?
Quantity - getting close
Quality - closer
Overall prefer the scottish stuff though not ridden BPW
Natural? Probably scotland.
NW doesn't have enough BW access to get into the proper mountain for instance. The remoteness of some of the scottish stuff is an issue and makes some of it more challenging to get to/complete
Quality of rider even around the world there are some great some crap and plenty in the middle
Which would I live in?
Neither. Best location for MTB that I have tried living is the Lakes, compact and lots of riding in a big variety of styles.
Scotland and Wales are both doable for a weekend or more.