My Berning zh270, 12 + years of ownership and frankly a product that has to date not shown me ANY limitations with the right speaker. It is in demand for good reason, the value/performance/efficiency quotient is unparalled compared to any amplifier I'm aware of for ALL the genres of music I listen to. Limitations that's the key word. While no product is perfect or ideal for all applications, or tastes for that matter, some just get closer to the ideal, this one does for me. It has never stopped amazing me since the day I purchased it and along the way, the tweeks to enhance it's performance.
Of all your gear, what piece impresses you most?
I like all my gear, yet the single piece that blows me away the most is my phono preamp.