I am very surprised that no one has mentioned the Sound & Vision article on page 28 of the July/August edition "Down With Tubes".
I will only type out the first sentence or so, if you want to read the article, buy the magazine, below is a direct quote:
"Okey, Internet, get this: tubes are a waste of money!!! They're hot, they're expensive, and one prominent manufacturer of tube equipment told me some years ago that the tubes themselves have something like an 80% failure rate. And they don't offer better sound."
If you want to agree or disagree don't flame me, this is a direct quote from Sound and Vision magazine.