so i decided to compare (with the best of my abilities) the difference in Photoshop's HDR and Photomatix's HDR and this is what i came up with. the top left is the original at what the camera thinks is the proper exposure; beneath that is the best i could come up with in Photoshop CS2 using 5 exposures; the two on the right are Photomatix, 3 and 5 exposures.
i just could not make the PS one look any better than that. i dunno.
these are both made from the same single RAW file and the same number of exposures. on the right is a 100% crop from it.
well, PS seems to make a more "realistic" picture i suppose, but right now, i'm just really enjoying how much more vivid Photomatix makes it. so for my money (maybe "time" is a better unit of measurement here), i choose Photomatix.