Modern pianos are better suited for concertos because they produce more volume. The brass frame allows the doubling and tripling of strings as notes get higher. The tension from that many strings would cause a wood frame fortepiano to buckle. It's also worth bearing in mind what they called a large orchestra in the days of the fortepiano, we'd call a chamber orchestra today. Fortepianos didn't have to compete with such a loud orchestra.For solo/4 hands/2 pianos things, I like either one. For concertos I prefer the modern piano.