I've had a Prologue 5 (maybe a slight upgrade from the 4, but not sure anyone would notice) for a bit over a year. It is a very nice, well constructed item. Sounds good and easy to use (self bias, etc). I found a significant improvement in sound with tube rolling, and ended up at Bugle Boy 12au7, Sylvania 5751 triple mica (12ax7), and Tung Sol 6550 power tubes. A very nice sound on my system (played though Klipsch Forte speakers). There are caveats, of course. Different tubes probably required for a different system in terms of speakers and sources. If you have low efficiency speakers make sure the Prologue has enough power (driving it real hard puts you in a higher distortion region, and a bit less desirable). There are no doubt more expensive amps that sound better, so as always it depends on your price point. My brother was looking for an amp, so I pointed him at the Primaluna. He purchased one and is VERY HAPPY (and listening to stock tubes). I think there are also some quite good values on the preowned market. I think it is an excellent entry tube amp, and could well be all you ever need.
