CUF deserves a lot of credit. They were in there to affirm, defend and advance the Catholic Faith from 1968 on, and for many years they were about the only ones in most forums, and in many cities. It was a thankless task: they took on the “catechetical establishment” at a time when most laity had not heard there was such a thing.
They had to deal with some people moving over to SSPX or other groups on the Right. They consistently refused to attack bishops or the pope, even when actions were taken usually by bureaucrats that they accurately saw would harm the Church. They knew attacking Pope Paul or Bishop X would do more harm than good to the larger cause. But they also provided laity with both spiritual formation, and the specific data they needed to redress some abuses in a charitable, non-spectacular way.
This always left some members unsatisfied, who wanted a press conference or bold public confrontation to announce that Bishop A was undermining Christian faith, which the Church’s media enemies would love to see. Instead, CUF avoided making points, tried to make slow, measureable progress instead - always low key.
In recent years it disappeared in my city, and nationally seemed at times to be undecided on how it fits in today. The difference between 1968 and today is that most local dioceses are less of a problem for orthodox Catholics, but the secular environment is much harsher against Catholics.
I would ask a prayer for those who over the years took low paying jobs, or no pay at all, to work in CUF. If ever there was a small group that did valuable work and never got appreciated, this is it.