as a disadvantages i can add:This statement is quite true, but I should point out that in any high performance audio equipment, whether tube or solid state, the devices used have to be hand picked- you can't expect to just buy them off the shelf and have them work.
Tube Microphonics, Tube Noise, Tube Rolling effect (you change the tube and you change the sound). The price for each good tube, the tube estimate hrs and short life of the tube (not good for very expensive nos).
Some years back we experimented with semiconductors at the input of our MP-3 preamp. What we found was that regardless of the MOSFETs we tried, we had to hand pick them and out of 100 units, we found only about 7 that were quiet enough for use. In that regard we had an easier time hand-picking the tubes!
MM cartridges are of course a different animal as loading affects them directly, otherwise they can ring and cause distortion. The loading is usually a bit more complex- did you read the comments Jim made about them in the article I linked?
How many great tube phono stages available for less than $1k , not for $3k? Just curious.At least two that I know of- but that IMO is a loaded question. In the preamp I'm thinking of the phono section causes the preamp to cost about $400 more that it does as a line stage. In another example the phono section raises the cost of the preamp by about $800.00; so I think the answer is probably a lot like 'a bunch'.