In D-76 (for highest quality), TMX is fine at 40 (OK at 80
in Acufine...), but VERY unreliable - and failure is NOT
permissible in commercial work! TMY has NO shadow detail
in D-76, and is unique in that pulling (even to 25 ASA)
does not provide shadow detail. It's mid-tone speed is
about 200 (whoopee! ;-), while the highlights are nearly
unprintable. Developers that tame its contrast, increase
speed, and provide better shadow detail, also remove its
grain advantage and the tones are ugly - Tri-X looks better
at the same or higher speeds. TMZ is merely odd, but fun
to play with (Tri-X true speed is almost as high).
I consider T-Max Kodaks sudden fall from grace - Kodak
always had avoided hype, and rated its products honestly,
'till the T-Max bag-o'-tricks appeared.... (during the
silver shortage, I think [these products pull EVERY
trick to get a semblance of speed and tone from silver-poor
materials...])