I haven't read the PDS UK forum, but I have used their excellent site for a number of things.

I don't class BT2 as a US site, it has members from around the world, Asia Pac, Canada, and Europe, and many others I have missed.

I don't think the tone of BT2 is reflective of any "nationality trait", rather it is the product of the people, from around the world, who have chosen to post and the admin policies of the moderators.

I imagine the PDS UK forum is the product of the same inputs.

Neil.