I guess it all depends on the speakers you have. If you have dry austere modern speakers I can see where you might find VPI's amp just the right answer. But I owned a 299D back in the days when I had Altec, Bozaks, and Stepens. Compared to my MA 230 the 299 was a flop. Even my MC 60's blew it off the map. It was a looser then and is even more so now. There is only one tube amp from the 20 th century I would consider and thats a MC 3500. And its not because of the power, but because of the quality. Ive owned Scotts, Fishers, built Dynas of all types, Installed Sherwood, Marantz and owned 5 different Mac tube amps, had friends with Citations,Pilots, Eico and heath kits. If I ever see another tube unit it will be tooooo sooooon.
It all depends on how a particular speaker A combines with a particular amp B being supplied by a source C. It was true then and is true now. The old rule of thumb then was the Speakers should be valued at 1/2 the price of your system. So if you have $10,000 to 12000 tied up in turntable and integrated amp, you should have the same amount invested in your speakers. I guess that means a pair of Klipsch kornerhorns, Cornwalls. big collectors JBL's, Altecs or EV's. If you don't your system is most likely dynamically challenged. 40 watts doesn't go very far with a speaker rated at 86 db/1 watt 1 meter. I will say a tube unit can help big Tannoys that can be excessive in the top two octaves.