My favorite of all time is D-76, but my workflow doesn't need these large stock solutions. I keep throwing them away.
Therefore I use HC-110 for convenience, consistency and economy (I come home, mix a developer, process a film or two and that's it).
TMAX dev I have used quite some time because it obviously is for TMax films. When it was my first choice I also used it for all the other modern T-grains, with nice results. Very convenient to use but I kept buying new bottles all the time, and the result is just as good as HC-110 or D76. As far as I am concerned the value in TMax dev is pushing, allthough D-76 and HC-110 aren't bad either.
Personally I have a very hard time seeing the reported differences, if any.
99% I shoot box speed, and I work hybrid a lot these days. My favorite push is HP5+ to 1600 (looks metallic to me), and in my eye all 3 developers work the same.
Therefore I do not use TMAX dev any more.
This might be an interesting analysis, from a well known authority (ultrafin plus read TMax dev):
http://www.imx.nl/photo/Film/Film/Film/page39.html
Quote Erwin Puts:
"Current films and developers are less sensitive in creating grain and sharpness effects as has been assumed over the years. Sharpness impression is mostly the result of an irregular pattern of grain clumps of various sizes. And the larger the size, the higher the sharpness impression. Tri-X looks sharper than Techpan. Tri-X film is not so good for testing lenses, as it creates a sharpness imression that is not based on the optical performance.
Acutance effects can hardly be demonstrated and if they exist, they operate on a subtle level.
Developer choices are not so effective for current films. They do influence the grain size and distribution and gradation, but the enlargement factor to show the effects is often beyond a normal users work style. (more than 20 times enlargement)."