Compared to a Miraphone 291B Bruckner 5/4 C-Tuba, which costs almost four times as much, the sound is surprisingly good, although naturally smaller than the large Miraphone. The overall intonation is a bit high, but the main tuning slide offers enough adjustment. The intonation is, however, surprisingly even (challenges are, understandably, different on different tubas and in different registers). The fifth valve works perfectly and is essential for practicing the same repertoire on the ZO as I play on the big Miraphone. I'm an amateur (definetly not a very skilled tubist). However, a friend of mine, a professional tuba player, agrees all of this. I bought the ZO as a "cottage tuba" for practicing at my summer home, but I believe it would serve gigs in small ensembles too.