I own a Spyder3Print system and I have a profile for Epson's Hot Press Natural White built with an i1 (also v.1) and I have the Epson driver profiles (which really are very good). I print on a 9900.
The Spyder profiles are nice. Not accurate, but nice. I use the custom one I mentioned above for Hot Press and the driver profiles for any other Epson paper. The only time I use a Spyder profile now is when I have to reprint something that I proofed initially through one of them.
I use the printer to reproduce artworks which I have scanned / photographed very carefully. If the colour is present in the file I need it to be present in the print. I don't want to be adjusting tone and colour to counteract the printer profile, which is what I had to do with the Spyder profiles. They introduce colour, saturation and brightness shifts that don't happen when I print through the driver or my custom profile. Blues pick up magenta and the yellow-orange-reds come out too saturated and bright, shifted to orange. There are other subtle shifts but those are the biggies.
What's more the Spyder profiles don't respond in the usual way to different rendering intents: Relative with Spyder is not like it is with an i1 profile, it's more like a perceptual rendering and BPC makes little or no difference to the output. Perceptual and Saturation are identical in output to Relative for in-gamut colour but out-of-gamut colour is dealt with differently. Saturation deals with OOG colour a bit more aggressively than Perceptual. Saturation with no BPC is the recommended intent for Spyder profiles! And it works! OOG colour is actually rendered quite nicely, albeit with the shifts mentioned.
If I was just printing my own photos casually and not trying to reproduce artworks then I would be very happy with the Spyder system. If I had known two years ago what I now know about the system I would not have bought it, but that's experience, right? The profiles are good, they give you good soft-proofing predictability, good shadow detail, pretty good BW output and a unique way of dealing with OOG colour. They do not do accurate colour, at least not accurate enough for me.