I think I glimpsed the John Smedley one on google images and the colour was a bit vibrant for my tastes. I like the colour of the Allsaints one, but it hardly qualifies as a 'classic' rollneck in my books. It's far too contemporary in the way the neck falls.
That's not to say you shouldn't get it, only that it might not be quite what you're looking for.
My most 'classic' rollneck is by Calvin Klein: it's 100% merino wool and in dark navy, fits like a dream and feels wonderful against bare skin. I think if you're looking for a more versatile piece, navy is the way to go.