David Robinson wrote:

I care about what they look like, but care about buying something
that's reliable / doesn't leak / will work when I need it to.

Given that I need 10-14 of the things (not sure every radiator needs
one, or has the space for one), cheap would be good too.

Anyone got any experience with either of these? Or others?

Depends what you've got below or near the lockshield, in cases where
there would normally be an elbow, I tend to replace with a tee, and use
one of these

http://www.uk-plumbing.com/bmz_cache/0/066d94da3f8e52c0379384e55ec5c968.image.250x250.jpg