Yes, it's worth it — and I'd happily put Little Greene at the top table of premium British paint alongside Farrow & Ball, Mylands and Paint & Paper Library.
Here's why. Little Greene's colours have a depth and complexity that cheaper paints simply don't manage. They use generous pigment loads and, in their flat emulsions especially, the way colour shifts through the day is gorgeous. The range on FiniSpec runs 251 colours with an LRV span of 0.4 to 98, so you've got everything from near-black to barely-there off-whites. The greens are particularly strong — 48 of them — and they're properly good, with the kind of murky, layered tones that read beautifully in real light.
Where it earns its keep is durability. Their Intelligent Matt Emulsion is wipeable and tough enough for hallways and kids' rooms, which is where standard chalky mattes fall apart. The Intelligent Eggshell and Intelligent Satinwood for woodwork are some of the most hard-wearing water-based trim paints going — they level well and don't yellow like old oil-based finishes.
A few colours worth your time: Little Greene::Air Force Blue is a deep, confident blue-grey that's brilliant on joinery and panelling. Little Greene::Hollyhock is a rich, dusky plum-pink with real warmth — gutsy in a dining room or a snug. And Little Greene::Mister David is a soft, sophisticated grey-green that behaves itself in north-facing rooms where a lot of greens turn cold.
The "but what about the price" question: yes, it's roughly the same money as F&B, around £55–60 for 2.5L. That's a lot if you're doing a whole house. But the coverage is genuinely good and the finish lasts, so you're not repainting in three years. For a feature room or hardworking woodwork, it pays for itself.
My advice: don't paint a whole house in it if budget's tight — use it where it counts. Buy a sample pot, paint a big A2 board, and live with it for a few days before you commit.