Well suited for a company with low to medium-duty print needs, or for a company that isn't ready to lease or purchase a commercial copier. Not well suited for a company that prints a lot of pages in a month, or for a company that only wants to purchase one model of toner, because they are not very interchangeable.
If you are using it for large-scale printing such as printing plans as we do, this is a great machine to have in your arsenal. Sure, the size can make it somewhat cumbersome, however it is definitely worth it to have in your office. It allows you to print full-size as well as scaled sheets at a myriad of sizes. It also allows you to scan and download edited drawings which is also a major plus.
We use a third party to service our machine so service-wise, it is hard to say. Support-wise, we have plenty of paper stocked and toner on hand should we run out. In my 4 plus years here at the office, we have had maybe one or two times where the machine was down for a day at maximum and then was back in working order immediately.
Cost per page is a lot better than the Pixma Pro. You can purchase replacement parts for the HP more easily if something is to break after warranty. The cost of ownership is lower than the Pixma Pro due to the Pixma Pro being a throw away if something was to break on it.
We also use this machine in our office in conjunction with the Teriostar. In comparing the two, the Teriostar is much more versatile. The quality of printing (and ability to print in color) is a big plus for the DesignJet, however, we can do so much more with the Teriostar. In looking at size, they are both comparable in that category.