I very pleased with my Freya + which I use most often in 'Passive' mode.
The Freya + is driven by my Topping D90 which as the uhmph to drive my amp, a VTV Purifi, with adequate gain and dynamics without resorting to the solid state unity gain 'Buffer' mode.
'Tube' mode is nice with certain sorts of music. I like it with Jazz and some popular genres, however I mostly listen to Classical music and find the usually 'Passive' delivers the best transparency.