Hi Bernard, the XpressO and the Roland as inprinciple the same age: they both use samples. The Vl70 uses mathematical models of the instruments, wwhich means they react the same as the akoustic instrument. Like on the real instrument, when you blow to hard is overblows, generates the same overtones, so sounds more realistic. The learning phase is also a bit more than compared to a sample instrument..
Though rather old, people still come to check wat synth i used for some sounds..