I'm surprised by this...the 1000i indicates 1200 dpi resolution whereas I believe the 5500 is maxxed at 600. I've used an older Encad 850 for large format fine art photographs and it was excellent. I would expect the 1000i to produce even better results and nearly equivalent to the Epson 9600/10600. No ?
The Encad 1000i can run 1200 dpi as can the HP5500. However, for most media they are run at the lower resolution of 600 dpi.
The Encad 1000i does produce a far better print than the 850. I had an 880 for some time and there is no comparison in the print quality between the 8xx series and the 1xxx series. No comparison at all. The 1000 series is also must less fussy and has a more reliable print head and ink delivery system. The Quantum dye inks on the 1000i are very nice and high gamut too.
In terms of image resolution and comparing a thermal aquious printer (Encad/HP) to a piezo Epson 9xxx the Epson will win. Technically the Epson print heads are of a lower resolution than the others but the machine makes up for it with really effective variable droplet sizes and lots and lots of passes.
To summarize, the Encad will not produce a print like the Epson. The smaller dot size of the Epson, the variable drop size, and the increased resolution really can produce a continuous tone image were dots are not visible to the naked eye. The Encad and HP cannot. However, the Encad and HP, depending on settings, can produce salable prints at speeds over 100 sq ft an hour (depending on how you configure) whereas that Epson 9xxx might average around 20 sq ft.
If you want to do ultra high end, get yourself a new Epson or a cool new Canon. If you want prints which are still very nice and which can be produced quickly get yourself a Encad or a HP. If you want to do serious trade show work, get yourself an Encad or an HP.
As an aside, I do have a 9600 here and I only use it to proof our drum scans. Any print for pay job goes to the Encad/HP or our solvent system.
Rob