Maxell or TDK?

It all depends on the deck being used. You should try both and see which brand gives you better results!

One important issue is which manufacturer made the most consistently good HIGH BIAS tape vs METAL tape where the prices became a significant factor, but were still within reach of most consumers.
But i wouldn't make an argument over "metal-master" grade tapes ($5 or more for one tape) since i have never performed any comparisons on that level.

yogiboy is correct. Your deck matters here. I have a 3 head Aiwa that sound better with Maxell. But my 3 head Nak? TDK was the way to go. Either will give great results in the right deck.

Both are well made. I still have tapes I made in the 70s and 80s, and they seem to be holding up quite well physically. Magnetically? Don't know. I occasionally had pressure pads fall off though.

The tapes I used were TDK SA or Maxell UD-XLii

I remember I used to buy tape by the case at a pro audio shop on Canal Street in NYC. Haven't been their in years and years. The TDKs were a quarter cheaper per cassette.

In my past experience, the Maxwll UD had a more extended top end, but the best TDK (can't remember the name) was really smooth and refined.

But my 3 head Nak? TDK was the way to go.

Makes perfect sense, since TDK manufactured the tape that Nakamichi sold under their name.