I think you've been hit on the head too many times before you get on a plane Mr T. HAHAHA!! How could the 1400 possibly have better shadow detail than the x900 printers, when it has just 1 single black ink and the x900 has 3?? It simply couldn't be possible unless you were comparing the x900 in it's worst case scenario and the 1400 in it's best case scenario.
When you say the 1400 has better shadow colours, do you mean better colours or better detail and separation? With half decent custom profiles and careful editing in Ps using some luminosity masks to control the mid and shadow tones exactly as one wants them, not just leaving an image as it is and trying to let the driver take care of everything, there is no possible way that the 1400's single black ink and vastly inferior print-heads and general print mechanism could be any better than the top of the range printer from Epson.
I have a 3880 and I know that with my work I have absolutely awesome performance in the shadow tones for detail, seperation, linearity is near perfect and so on. I would really like to know where you have seen the printed output of the 2 printers you mention and the 1400 giving superior results. What papers did you use in each printer and what profiles were used?
Regarding ink fading, again, the pigments in the x900 will last SO much longer in real world use, there is almost no comparison. The tests Wilhelm does are accelerated and not really much like real life, actual conditions in which one would have their work on display. There is SO much more UV in real life light, it's very possible the prints could be exposed to sunlight also, not just kept in a dark drawer somewhere.
Those tests are not for use of the prints in real life, on a wall, etc. They are primarily to be able to compare different brands of inks, papers and so on in a non-variable environment, NOT how these prints would react or fade in a real-life situation.
If on a wall in a house or office and being exposed to pollutants, sunlight and UV, I can guarantee that the pigment inks will outlast the dyes without any doubt and that there is no way the 1400's DuraBrite inks will get to anywhere near 1/2 the life span of an x900 pigment print.
But please let me know what papers and profiles were used, re: better shadow colours. Very interested to find out.
And welcome to the PrintRoot forums buddy!! Hope you keep contributing to our little part of the interweb.