BBC Advocates use of Arial
bbc.co.uk
bbc.co.uk
Boring, but workable. Yeah, I know, Arial bad, Helvetica good! -- never got any part of that argument. Both are quite boring Grotesques… (Still waiting for a high-dpi monitor that can finally end the reign of the sans serifs)
Apple, OTOH, properly licenses Helvetica.
And whether it's a straight clone can be argued, too. Basically it's to Monotype Grotesque like Helvetica is to Akzidenz Grotesk. It's a bit too close to comfort for some designers, but there are lots of fonts in that design space that aren't that different (one of the problem with grotesques). The shapes of the glyphs don't match, but the general footprint is the same so that you easily substitute Arial for Helvetica and won't change the flow of the text. By the way, this is basically the raison d'être for Liberation Sans, which shares the same metrics.
Also, if it were a straight carbon copy, designers wouldn't complain about the ugly looks of Arial as compared to Helvetica. Which I never quite got myself, but then again, I'm not Helvetica's biggest fan.