I just replaced my HP Z3100 after three and a half years of light use. After my experience with this printer and HP customer service I have vowed to never buy from HP again.
The printer worked flawlessly for the first three years of use. Then the carriage drive belt started to crumble leaving bits of rubber in the print path. The bits would get printed over and then later fall off leaving white spots on the image. I had the belt replaced at considerable expense and the printer performed like new again. For a few months. It was a downward spiral after that with various obscure error messages that required calling HP customer support (they charge for support calls if you are out of warranty). I ultimately decided that it was costing too much money to keep the printer on life support.
Other things I disliked about the Z3100 include difficult paper loading, ridiculous single sheet handling, and inks that expire. WRT the latter, my dealer never told me about ink expiration and happily sold me a load of replacement cartridges, only to have them expire before they were ever inserted into the printer. The Z3100 is frugal with ink, I will say that much.
I just replaced the printer with an Epson 7900. I am impressed by the overall build quality of the machine. It seems sturdier than the Z which would rock back and forth with the movement of the carriage assembly. It is also faster and quieter than the Z, after the initial start-up period, that is. The fine print detail clearly exceeds the capabilities of the Z as well. And paper loading, both roll and single sheet is a dream compared to the Z. Only time will tell how happy I am with the reliability of the 7900.
In any case, no matter what you buy, I would seriously consider an extended warranty. So you may want to price that into your purchase decision.