I like both, depending on their use. For sociability, the swivel are great. For writing or some other, more 'stationary' function, the stationary are it. The swivel is too much work to keep it stationary!

I have lived in two places with breakfast bars in American style kitchens. I found that I tended to spend a great deal of time sitting there so a bar stool with a comfortable back is important. I made mine from pine, copied from some I saw in a bar. I was also given an old captains swivel seat from a yacht so I built a stand for it, reupholstered it and unfortunately left it for the new tenant who liked it. That was one of my favourite seats, to sit in comfort at a breakfast bar rather than balancing without a back to lean on.

Depending on what colour your kitchen hardware is, there a couple of options that would work well in a graphite kitchen. If you have white worktops and a grey kitchen, I would add another colour or texture to the stools to create another layer to the scheme. If you don't like using bold colours, you could use an interesting textured metal or wood for the stools. You could try using something similar to the silver wire stools below for a more industrial style Or wooden stools are always lovely for a more contemporary country look. I would use a lighter wood, to add contrast to the dark grey kitchen and white worktop All the best with your project

Google says potterbarn.com do, but not here in the UK. Houzz shop is just links to other stores.