I posted a very large excel sheet with comprehensive data on TDK SA tape.
The "legends" prevail of railroading, cupping, dishing and chewed tape, and I was in a position to collect REAL data from a large lot of used SA tapes I had (at that time) recently acquired. It is posted on TH somewhere, but some searching there should find it.
My conclusions were that yes, those things happen. And that they happen to ALL tape brands. The reason for TDK being the main target for these "problems" is simply the volume of TDK tapes sold globally- there are just more of them out there, and like everything else, you only hear the "bad" news. But the percentage of "failure" is no more than any other brand, based on my data. Note that the tendency for this to happen increases with tape thickness reduction. Up to 90 min TDK tape the issue is "average"- in line with others, but as you move to thinner 100+ minute tapes, the problems get worse. Add to that the general condition of 40+ year old tape decks with questionable maintenance, and all of a sudden there is a "crisis" with "bad" tape.
I have SA tapes I recorded in the mid-80's that still sound fine. And that big lot of used tapes was several vintages, several lots within each vintage and totally unknown treatment (temperature swing, cased or not, shock/vibration) prior to my receiving them. So, they represented a good sample of "used" tape.
Another neat data point is consistency. SA tapes starting in 1983 (when the tape color went to a dark chocolate brown from milk chocolate brown) right through to the bitter end with the shit glued shells, all perform and bias very closely to one another. Like laboratory test consistency. I found that to be the most impressive data point over all the others. If you have a deck where you cannot set fine bias manually every time you record, having a deck set for SA tape will always record well regardless of tape vintage (post-83).