Upload & Sell: Off
I used Imageprint for about 4 years on a windows XP system driving an Epson 2200 printer. The main reason I bought it was that it nailed B&W (perfectly neutral) when no other method I tried on the Epson 2200 could do that. Color prints were good too, but not significantly different from color prints produced by printing with Photoshop using Epson drivers and canned profiles.
Two years ago I upgraded to a Windows 7 machine and got an Espon 3880 printer. Colorbyte would not sell an upgrade, but I was pleasantly surprised to find that the Epson 3880 produced very good B&W using Epson driver and canned profiles. Excellent color prints too.
At about the same time, a member of my photo club also bought an Epson 3880 and Imageprint to drive it. He produced a set of 11x14 comparison prints using Imageprint vs. Epson driver and profiles. He brought them to a club meeting and several members reviewed them.
Bottom line - most people had trouble seeing any differences in the color prints at normal viewing distances. Only when the prints were layed one on top of the other and inspected very close could differences be seen. And even then, opinions on which was better were mixed. The B&W prints were virtually identical.
The color prints were all on Epson Premium Luster paper. There were two sets of B&W, one set on Premium Luster and one on an Epson Matte (with matt black ink, but I can’t remember which paper. I think it was plain old Epson Enhanced Matte).
The conclusion was that Imageprint was not worth the additional investment, at least on the Epson 3880. In my opinion, Imageprint got its good reputation and had value 5+ years ago when printers were not as good as they are now. But the current offerings from Epson, Canon, and maybe HP are vastly improved over old technology. Imageprint may still offer an advantage, but you have to decide if that advantage justifies the significant cost.
The Imageprint advantage is probably greater if you print on a wide variety of papers from different 3rd party suppliers. But in the example of Epson printers on Epson paper, I don’t think Imageprint is needed.