So the logic of more patches = better profiles is sound in theory. There are however a couple things to consider. Firstly 3rd party profiling software needs to be able to generate profiles for any device, be it a 6 color offset press, a large gamut inkjet printer, or a toner based copier. To accommodate different devices the internal engine needs to be adaptable, and so therefore having more sample points can sometimes offer a noticeable improvement in the profiles, especially with CMYK profiles. With the HP color center the engine knows more or less what the gamut of the printer is. The result is that the color profiling engine has been optimized around the Z31/3200 characteristics, allowing it to produce very good results from fewer patches.
Even when thousands of points are sampled the software may not make equal use of all of the additional data, and virtually all software "smooths" the resulting measurements. There is usually a trade off between accuracy and smoothness of a profile, with photographic output generally favoring the later. What goes on behind the scenes is usually more important than simply the number of profiles being feed to the software.
The APS adds the ability to produce CMYK profiles, useful if your using the printer in conjunction with a RIP or if your going to use your Z series to build profiles for other printers you own. IT also provides basic profile editing tools, and a monitor calibrator, giving you a complete color management package. I've done the tests and I'm generally happy with the results from the color center, but if you need more versatility the APS may be of interest.
Yeah, right now I have a Pantone Huey Pro, which is OK, but I think I need a better solution.. it's a close match, but could be better. That said, I'm also on a monitor (LCD) that's 6+ years old... Samsung 191T, so bumping to an LED (I just with Apple went with something other than that damn MiniDisplayport) monitor and new calibration will really help increase my accuracy, especially since my 191T is taking longer and longer to turn on (I think the backlight is sloooowwly dying. )
And I don't understand why Apple's Cinema 24" with the LED backlight is $850 and the closest equivalent is the Samsung or NEC at $2400. Unfortunately there are no available display adapters with the mini Displayport as an output option so you either need to buy a Mac (which isn't going to happen) or wait for some card MFG to license it (it's free from apple) WHich I would think they would do because there are people with older macs that are going to want to use the new monitors... so keeping my fingers crossed, but I still also don't dig the shiny gloss screen... But that isn't worth the $1600 difference in price!