Sounds like the mid 80's all over again. Back then there were endless articles and studies about the safety and attractiveness of Junk. How did that work out for all the people who followed the hype piled into Junk in the pursuit of high yield (exactly like they're doing now)?
It is worth mentioning that Milken got this asset class accepted as legitimate by downplaying its risks. He blurred the distinction between junk and fallen angels, a safer asset class. Since junk trades at par, downside potential is far greater than upside.
With junk, investor losses far exceed default rates, because any given junk default has a far more damaging effect.
Last but not least, people are piling into junk now not because they understand this asset class and consider it a good investment but because it is being hyped by Wall Street as a superior yield vehicle.
People entering on greed will exit just as quickly on fear. This looming threat of mass exodus is an even greater risk for investors than the other issues I point out above.
Take a look at what happened to JNK in a one month period, beginning in August 2008, and keep in mind that now these ETFs have attracted even *more* money than before the 2008 crash.
If SJB isn't a buy right now I don't know what is. Of course no one knows when the bubble will burst, but patience will pay off.