All digital negatives require application of a correction curve so that the tones of the negative match the UV response of the emulsion they are intended for. There are basically two places you can apply the needed corrections. One, you can apply them to the digital image file, before it is sent to the printer. This is fundamentally the method used by Burkholder, Nelson, and many others. Two, you can leave the image file alone, but apply the corrections to the printer's ink settings. This is the method that uses QTR. The disadvantage of method one is that the correction curve is usually quite severe and inevitably results in some image degradation. However, it applies to any and all printers, not just to Epson printers. The advantage of method two is that there is no degradation of the image file, and one has complete control over the printer's inks (which allows some subtle manipulations not otherwise possible). But, QTR is only for Epson printers (sob). I really wish someone would step up to the plate and provide a QTR look alike for Canon and HP printers as well.
Bottom line, you can make really good negatives and prints by method one, on essentially any printer (take a look at some of Burkholder's or Nelson's work). You are not screwed by lack of an Epson printer.
Good luck, Ron Reeder