We live in a Church crisis right now, and many souls are in need of being assured they have tried and true sacraments. That overrides any scruple of jurisdiction simply. The Church simply supplies jurisdiction in this crisis we endure now. Some would disagree, of course, but remember that having ordinary jurisdiction is something that is supposed to ensure the faithful of valid ministers for confessions and marriages, but right now we do not live in an ideal situation for the Church. The canonical system would end up working against the mission of the Church to save souls if it were not for the supplied jursidiction ensured by the Church in times of crisis like our own. Sadly, now many priests in the canonical structure would not dispose many most properly to the sacraments of confession and marriage. It would be best then to go to a traditional priest. For one thing, it would be like living a double life if a Catholic has to always worry about going to confession with a NO priest and then attend SSPX or independent chapel Masses. The mission of the Church is not hindered though, and so it would be best to get the "full package" so to speak.
I believe the N.O. confessors I go to are valid - although they are sadly misguided - or else I would not go to them. I don't think they give good spiritual advice - the ones I go to usually don't give any advice at all - but I can get spiritual advice from a trad priest after confession, so that is not such an issue. Although I think a revereant N.O. is not as pleasing to God as a TLM, since it is a Protestantized, watered-down version, I do believe that a N.O. Mass is still valid (unless proper matter and form are not used). When I am unable to go to a TLM, either because there is none or I am too tired to wake up early, I have to go to a N.O. Mass to fufill my Sunday obligation- although I follow along with my own prayers and try not to look up until the consecration.
Although there is a crisis in the Church, I don't think that a person is unable to go to confession to a N.O. priest because N.O. priests are still validly consecrated and their sacraments are still valid - unless you have one of those churches that have the outrageous abuses (then I would not go to their Mass or sacraments since I would doubt the validy).
Perhaps Keph is referring to the fact that many N.O. priests are no longer able to be depended upon for Confession for various reasons: 1.) They don't always follow the form that is requisite for the Sacrament to be valid, (a good example, for a priest to say, "Go in peace. Your sins are forgiven" without ever having said the words, "I absolve you.")
2.) There are potential graces in getting good counsel and obeying your Confessor. If he doesn't give good advice or any advise, you lose out.
3.) They aren't likely to offer optional penances. (Most have no clue what this even means nowadays.)
4.) They aren't as schooled in natural law, having studied in seminaries that propogated modernistic heresies. This means that they are seldom equipped to even comprehend the sins and/or their root causes. They may play down a sin, or even dismiss it as venial when it is mortal, or a venial sin as not a sin at all, or sometimes some priests will even dismiss mortal sins as not being sins or merely faults.
5.) Because of the reasons above, I find that such Confessors are a danger to the faith, albeit, in they have the ability to administer valid Sacraments.