These are two of the finest paint brands you can buy, mate, so you're not going to go wrong either way. The choice comes down to range, finish character and the look you want.
Benjamin Moore is the heavyweight on choice — 3,883 colours versus Farrow & Ball's tighter, curated 301. If you've got a specific shade in your head, BM almost certainly has it. Their strongest families are Greens (610) and Neutrals (429), and the LRV range runs a wide 4.6–90, so you get genuine near-blacks and proper bright whites in the same fan deck. The Aura and Regal Select lines are seriously durable and scrub-resistant — cracking for kitchens, hallways and family bathrooms. Colours like Yellow and Turmeric show off how punchy and clean their pigments can go.
Farrow & Ball isn't about quantity, it's about depth. That curated palette of 301 is the point — every colour has been considered to sit beautifully alongside the others, with LRVs from 5 to 92. The Estate Emulsion and Modern Emulsion finishes have a soft, chalky, light-absorbing quality that flatters period rooms and changes character through the day. Their greens (67) and blues (41) are the standout families. Acid Drop shows their willingness to be bold, while All White is the cleanest, most uncomplicated white in their range — no underlying tint pulling it warm or cool.
The "but what about price" question: BM and F&B sit at a similar premium tier, though BM often works out slightly better value per litre and covers more reliably in fewer coats.
My honest steer — for a period property or anywhere you want that quintessentially English, atmospheric feel, F&B earns its keep. For maximum colour choice, harder-wearing surfaces, or a precise shade match, Benjamin Moore wins. Get sample pots of both and test on the actual wall before you commit — pigment behaves differently under your light than it does in a showroom.