(1) I suppose the only fair and impartial statement would be that each of the printers, and manufacturers, has its own set of strengths and weaknesses. So you need to decide on your own.
(2) How many of the forum participants have personally owned and used both the Z3100, and one of the other printers that they might recommend? The only valid and honest comment would be from someone who has owned and used both the Z3100 and one of the current Epson or Canon printers.
For full disclosure, I have not. My previous printer was an Epson 4000, and my comments below on Epson are based on that, so take them with a grain of salt since the 4000 is ancient by today's standards.
(3) One of the few who has actually owns and used all three manufacturers, at least that I know of, is Michael Reichmann. You might consider writing to him off line and see if he'll privately respond to you. Beware of those who get paid by any of the manufacturers to do reviews or seminars, or get free printers for doing so. Some of them have posted here in the past. Michael, to my knowledge, doesn't belong in either category. I may not always agree with his views, but at least he is not paid by a manufacturer or given free equipment and is thus impartial.
(4) But you need to provide Michael with more information that you provided here. To say "talk me out of it" is not very informative. What do you print? What sizes? How often do you actually print really large to need a 24" printer? The Z3100 is VERY LARGE. You need a separate wall in a separate room to house it.
How often do you use or try other papers? If not very often, then the on-board spectro in the Z3100 might be less important in your personal evaluation. But then you need to buy a separate and really good profiling package, and the good ones aren't cheap. Compare the price of a printer, plus such a package, to the Z3100 after subtracting any rebates that may still be offered
Do you print from rolls or sheets? If from photo sheets, especially 17x22 and smaller, then you look at a printer with paper cassette that handles those sizes. If from heavy and thick cotton sheets, then all of the printers will only allow you to load one at a time and are pretty much equal in that regard. Some may load sheets slightly better than others.
(5) If you search under my user name, you will find that I led a personal crusade against HP many months ago. So it is quite a change for me to now recommend HP. Their level of support is probably the best I have ever experienced from a large company, and they have won me over. That is an important factor for you to consider. Does Canon, to use one example, stand behind their products and offer that level of service? Never owned a Canon, so I will let John and others comment on that
(6) The case for the Z3100, very briefly:
* great customer service, as noted above
* I think it does a great job of printing -- the colors are more vibrant than my old 4000, especially the blues. The reds are very good IMHO, but it is true that some landscape prints from the 4000 had slightly, very slightly, stronger reds than the Z3100. Others can comment, but I think HP has gone a long way to fixing the issue with the reds. For me, doing landscapes, the Z3100 does a great job with all colors. Others, who make more exacting prints, might have a different view, and then the question is what printers they have personally used and would recommend instead
* The on-board spectro is a delight. I'm glad I no longer have to do manual profiling of papers. I use the APS. It is not critical that you buy that, but I believe the newer models of the Z3100 include the APS in a package deal. The APS, IMHO, is equal to and superior to the last $1000 Xrite package I purchased
* The level of technical documentation is simply outstanding. I have an entire folder on my hard drive consisting of 120 mb and over 50 documents. HP actually tells us what the various driver settings mean in terms of head height, ink delivery, etc. Does Epson or Canon do that? Epson certainly did not do so with the 4000. They only provided settings for their own papers, and I was always mystified as to which Epson paper setting to use with a third party paper. As I have posted here, I think HP can improve those documents. But they are already far better than what Epson provides, at least based upon my 4000. But judge for yourself -- download the docs from the manufacturers to see how much detail they provide about their settings and drivers. Note -- in the case of HP I am not referring to the manual but tech support docs that have been released and updated since that time
* There is an issue with ink building up on one specific print head. After nine months, it took me about an hour to clean the print heads. I don't think that is a big deal. But the issue of ink on the heads is something that HP is looking at, because, as I have told them, it shouldn't be happening on a $4000 printer that I use infrequently
* On the other hand, I have never had a print head clog up. The 4000 was NOTORIOUS for that. What is the record of the current generation of Epson and Canon printers? HP has, at least, solved that.
* The issue of marks rollers and star wheels seems to impact some Z3100 owners a lot; for some it is an inconsistent and infrequent problem; and for some it never happens at all. It is important to note that Epson has their own problems with marks with star wheels. HP will have a fix available in three to six months, in any case.
* Software. Well, I would stay away from Vista with any printer and for any use. See my posting on that. The basic problem is Vista more than it is HP.
If you using XP or a Mac then any of the printers should be about the same -- but you need to read the postings.
Candidly, I rarely read any of the postings in this forum on Canon or Epson, for the simple reason that I don't own one! (Aside from my original 4000 that I finally plan on selling for some cheap price just to get it out of here.)
I hope that helps