These two get lumped together because they both fly the eco flag, but they're aimed at different people, mate.
Earthborn is the clay-and-mineral specialist. Genuinely breathable, virtually VOC-free, no acrylics — it's the paint I reach for in nurseries, old cottages with lime plaster, and anywhere damp needs to move through the wall rather than get trapped behind it. The trade-off is the palette: 85 colours, with whites by far the biggest family (28 of them). It's a clean, chalky, contemporary range. White Clay is a lovely soft off-white that sits beautifully in north-facing rooms, and Flutterby is a cracking muted green-grey if you want something gentle and modern.
Edward Bulmer is a natural paint too — plant and mineral pigments, no petrochemicals — but its real strength is colour. 146 shades, and the depth tells. Greens dominate with 31 of them, plus 16 browns and 13 creams, all rooted in historic British and European interiors. If you're decorating a Georgian or Victorian house and want pigments that look right under both daylight and candlelight, this is the range. Silver White is a refined, slightly warm white, and Jonquil is a gorgeous soft historic yellow that's hard to find done this well anywhere else.
The "but what about durability?" question: both are softer than a big acrylic emulsion like Dulux, so neither loves a battered hallway with toddlers and dogs. For high-traffic zones, spec their more washable finishes or accept you'll touch up. Earthborn's Claypaint is matt and chalky; Bulmer's emulsion has a touch more body.
My steer: if breathability and a healthy, modern interior are the priority, go Earthborn. If you want serious depth of colour and a period-faithful scheme, go Edward Bulmer. Order samples of both and live with them on the wall for a couple of days before you commit — these natural pigments shift more than synthetic ones across the day, which is exactly why people love them.