How does the artisan Natural compare with the Vispring Devonshire

I have been and rested the Devonshire and other Vispring mattresses. The Devonshire appears to be my best option. I am looking for a softer feel and the mattress will be going on either a slatted or solid top ottoman. I have asthma and don't want a mattress with horsehair.
How does your artisan natural compare?