If you are happy with the Onkyo, then stay with it, and save yourself alot of money. Shiit Audio has preamps, power amps that sounds much like a tube sound. I compared, and I stuck with the Primaluna. I read another person liked Hegel better, but I compared my EVO 100 integrated directly against a Hegel 390. The Primaluna was the clear winner for detail, accuracy of instruments. A sax on the 390 did not sound right, wth primaluna was perfect. The 390, which way overpowered the EVO integrated, but just was not realistic in sound as the Primaluna. That's my experience. The 30wpc has no problem driving my speakers which are 89db sensitive, 70wpc rated.
