TDK SA-X or Maxell XLII-S which do you prefer?

Especially if you're using a NAK use the Maxell tape. Nakamichi sold their own branded tapes in some, but not all markets, and they were made by Maxell. Some say the formula differed somewhat from XLII, etc but others say they are exactly the same. I only ever had a few samples (not sold in my market) and I would say they are the same, going by the smell test, which is surprisingly accurate.

I'm out of practice now, but at one time I could easily nail about a dozen formulas blindfolded just by smell. Each tape formula has a very distinct odour, even within the same brand. Pop the tape into a plastic bag and let is sit for a day, then take a whiff from the bag. You will be surprised how easy it is.

Nakamichi tapes are re-branded TDK not Maxell.
Maxell XLII-S and TDK SA-X sound different on NAK, in most cases I prefer Maxell. SA-X Limited is better than regular but only 100min., no 60 or 90.

XL1-S is lower distortion.

XL 1 s is lower distortion, post got changed in the translation

IIRC, the TDKs were smoother, cleaner, but had more frequent dropouts. The Maxells were brighter, a little grittier, with a little more detail, and suffered less from dropouts. I didn't think anyone still cared. I digitized all my cassettes (well, the ones I lacked a CD or LP of) and now my really nice Onkyo TA-2600 (bought new in 1989 - 2 motor, 3 head, with real time and time remaining counter!) sits at the bottom of my rack, gathering dust.