Kemble vs Yamaha
This is a comparison with a twist, because for its last twenty years Kemble was owned by Yamaha and built with Yamaha parts. So in many cases you are comparing two close cousins.
The connection
From 1988 Yamaha owned Kemble, and Yamaha-era Kembles use Yamaha soundboards and action technology in a British cabinet. The Milton Keynes factory even built Yamaha-branded pianos. So a later Kemble shares much of a Yamaha’s engineering and character.
Tone and quality
A Yamaha-era Kemble has much of the even, reliable, clear tone Yamaha is known for. A Japanese-built Yamaha, the U1 or U3, is the benchmark and holds a slight edge in consistency and resale, but the gap is smaller than the price difference suggests.
Price
Here is the Kemble’s advantage. Because the name is less famous, a good used Kemble usually costs less than the equivalent reconditioned Japanese Yamaha. Pound for pound, it can be the value buy.