Back in 1991 I bought a pair of Mission 765 floorstanders. Being current hungry, I drove them with the NAD "Power Envelope" 2600 Power amp. I thought this sounded good until a friend of mine bought the same speakers but got a Denon POA-2400 power amp instead. The difference in sound was really noticeable. The Denon had this really open and fluid sound compared to a more hardcore edgyness of the NAD.
So for about 18 years I harboured this envy, wishing I'd opted for the Denon. This sounds unfair to NAD, the 2600 IS a good amp but probably suits heavy rock fans more than my kind of taste in music. The NAD is a tough cookie, I've driven it hard with these 4 ohm Missions but you have to really be in the mood to listen to the NAD at highish sound levels.
Then 2 years ago I spotted a POA-2400 on eBay. After a few checks, I took the plunge. A pristine amp, sounds as good as my mate's and I'll swear that when pushed, it goes much further than the NAD. The bass headroom is greater but most of all is that open soundstage, it's wide the sound has a seamless fluidity to it. Plus the build quality is truly exceptional. As a electromechanical assembly professional, I'm really staggered by the internal build quality of the Denon, it's way above commercial / domestic construction standards. Denon must have spent a lot of money making these amps. Indeed, people say these were made during the "Golden Age" of Japanese HiFi - it really shows too. If you're fortunate like I was to find one on the second hand market unmolested and looked after, you will get an amazing piece for kit for around £400 which is what I paid. A gem.