Johnny D.: Obviously my response will be somewhat biased. But I can tell you that buying links is simply not a good fit for everyone. There's an inherent risk involved when implemented poorly, both on the buyer's and the seller's part.
That said, I can speak from our end in that we deal with some very large paysites, well-known brands, paysite feeder sites, small amateur sites, solo model official sites, etc. for their hardlinks needs. And I see them buying consistently (at least from us) again and again, year after year.
And there are often times when someone needs something that I don't think is beneficial to them where I suggest they try a few other honest sellers on here (Debauchery, rebel-ads, matyko, MarcyM25, bloggerz, Ray, Denny (though he is less advertised these days), etc.) Due diligence is important on both the buyer's and seller's part.
The entire idea is sustainability versus a cash grab. There's a reason some of us, like those mentioned above, have been in this business as long as we have and continue to cater to clients large and small for so long.
I'm sure there are others I have not mentioned. That's not to say they are not worth dealing with. But rather that i just have had no dealings with them personally. In the end, just be smart about it and links are still a great way to gain traction. But it is not the only way to do it. They are extremely good used as a part of an overall strategy. And my opinion is that a strong strategy involves a healthy mix of nofollow, no pr, pr0, 1, 2, 3, 4, etc. Don't leave an obvious footprint
Good luck.