Wheity.n you're investing in a performance-grade grand piano, the choice often comes down to a battle between high-tech modernism and old-world tonal tradition. The Ritmüller GH series, are the flagship "Professional" line from the world's largest manufacture. The Kawai GX series is the known for Japanese engineering. However, the Ritmüller GH series offers a "boutique" alternative that prioritizes a warm, European soul.