So here comes the first post on the "production" ProcessWire based site. I am changing over from Symphony CMS due to problems accumulated during the years, and that I felt I really can't keep on refreshing my knowledge of XSLT which I only used to fix things on that site. In summary the goals of the two systems are quite similar, however ProcessWire seems to work better for my purposes.
Three years ago I changed over to Symphony CMS due to how I didn't like Drupal after some experience and theming of Drupal 6 and Drupal 7. The good thing was that Symphony allows the control of the whole composition of the site, for appearance the entire markup, but it also applies deep within, the data models. With that CMS, you set up your data models the way you need them. ProcessWire offers the same flexibility in this regard.
With ProcessWire these problems seemed to be non-problems. I could figure out the way to cross-link with proper templates in a few hours of various tinkering, then, using the HannaCode extension a very reliable method of in-content linking also came. Getting familiar with the structure of this CMS, I resorted to use the ID's: they are good since this way the content can be moved around freely, yet the links will stay valid indefinitely.
Some minor problems exist, though. The built-in comments feature still lacks text formatters (but they will come), so the Markdown in the comments wouldn't get interpreted. I didn't yet enable the comment form since first I will have to learn how to add custom validation to them (by the way this neither worked the right way with Symphony CMS, but at least it worked somewhat, preventing comments which I didn't want): I found that if I abolish URLs, spamming can be kept fairly low without relying on some external intelligence.
There are still several things to fix, such as to finish my plans with theming, a mobile device oriented theme in particular: right now I just disable the mecha-cheetah if the rendering area is narrower than 1000 pixels with the intention of swapping over once that alternate theme is completed.
So in overall this seems to be a quite nice thing, just what I wanted. PHP is great for theming (and seemingly utilized quite well by ProcessWire): there is no need to learn some arcane language for that which is a definite plus if one just wants to occasionally tweak a few sites, not doing it for a living. Otherwise the same like Symphony CMS: you design the data model and the presentation the way you want, unlike in the world of "Drumlapress" where you can never get exactly what you want.