I just bought PrintFIX PRO and made three profiles for my HP Designjet 130:
one with a 225 patch target for HP Premium Plus Photo Satin, setting Best,
one with a 729 patch target for HP Premium Plus Photo Satin, setting Best,
one with a 729 patch target for HP Premium Plus Photo Satin, setting Max detail.
The result with the 225 patch target was terrible. Maybe I'll do it again someday and see if I did something wrong.
However, both 729 patch targets show a subtle but noticeable improvement over the standard HP supplied profiles. In particular, transitions in shadow areas from black to near-black are smoother.
Also, the test targets that the wizard offers you to print before you're actually going to make a profile are quite revealing; I never quite understood the difference between Best and Max detail on the HP Designjet 130, but the test images show marked differences. In 'Best' green tends to oversaturate - some ajacent shades of green are indistiguishable, where 'Max detail' shows clearly graduated steps. Also, in 'Best', the transition from black to near-black is less acccurate than in 'Max detail'. The good news is that the profiles I've produced correct these errors; greens are more neutral and transitions are smoother.
On the whole 'Max detail' would appear to be more accurate than 'Best', but in an actual print with the new PP-profiles, I see no difference between 'Max detail' and 'Best', while they are both visibly better than the HP-supplied standard profiles, standard 'Best' being the poorer (while, incidentally, the standard profiles are quite good).
It's a bit of a misnomer - I've yet to see a print that shows more detail in 'Max detail' than in 'Best'.
Ergonomically, I found the easiest thing to do is clamp the target vertically onto a board of some kind in order to measure the targets.
I've attached a small jpg of my 'real world' test print, a 4x5 scan of Velvia 50, one of my most difficult images to print well.