I'm tempted to get one of these online, but I also really want to wait until I'm in London and visit one of the amazing looking stores there. Although I feel I may get carried away and spend way more than I intended!
Once you're spending more than £100 or so on a 21" chef's knife for example, what are you really getting more of?! I see the blue steel ones are mega $$$, and seem much more durable and hold their sharpness for much longer.
Aesthetics mostly. Like most things there's diminishing returns. You can get Aogami blue for under £200 https://cuttingedgeknives.co.uk/products/sakai-takayuki-aogami-super-blue-gyuto-210mm.
You can get slightly better performance but for 99% of people it's not going to matter. Anything you spend over £200 will almost always be purely for the aesthetics or as an art piece (Hattori knives, for example). Or just because you appreciate the craftsmanship.
https://www.youtube.com/watch?v=m5LWXXz2pHI < Don't watch the whole video, it's very boring. But it gives you an idea of what a properly sharp, well made knife will do.