The NRA slippies don't look bad but I would suggest either a US made Buck or Case XX.
I have no experience with Queen but many like them.
If you are in the UK maybe a Sheffield or Solingen slippie might be a good choice. I hear that Hen & Roosters and Boker slipjoints from Germany are quite good.
If you want to do some research check out www.bladeforums.com
and visit the Traditional folder and fixed blade sub forum.
I just bought a Case Moose in CV blades (carbon steel) and I am very pleased. The Moose is a 2 bladed 4 1/4 inch stockman.
http://www.wrcase.com/knives/view_all/firstlook.php?Family=%22Red%20CV%22&View=1&Item=
Even though locking knives are OK here I still usually carry a slipjoint for smaller tasks.
Bill

On second thought why not something like an SAK Farmer? That is a great knife that would be legal in the UK.

I don't think the NRA slippies are made by Benchmade I think they are Bear & Sons.