Anyone who says that the N.O. mass is "valid" and is therefore "ok", 1) is making the most generalized, blanket statement imaginable, or 2) doesn't know what they are talking about.
First, define "valid". Do you mean that the consecration MAY BE valid? If so, are you speaking about a PARTICULAR mass you attended, or, again, are you applying validity to EVERY N.O. mass that is said?
When one discusses validity of the N.O. one must differentiate between multiple, multiple scenarios.
a) the N.O. consecration of both bread AND wine were changed by Paul VI. You can't say this mass is valid unless you're sure that the consecration formula is correct.
b) The consecration of the bread REQUIRES "for many". If "for all" is said, it's not valid. If a poll were taken, i'd bet that many N.O. masses still say "for all". Benedict XVI just "rectified" the situation only a few years ago. Who knows how many bishops/priests "got the memo" and actually obeyed the pope.
c) the consecration of the wine is probably INVALID because the phrase "mystery of faith" is not part of the consecration formula, but is added in a prayer AFTER the consecration. THIS has never been fixed, talked about, or rectified, even though many new-catholics think the N.O. is now "ok" after Benedict XVI "fixed" the consecration back to "for many".
Conclusion: Who knows how many priests say "for many" vs "for all". But MOST if not ALL priests in the N.O. still say the consecration of the wine without the "mystery of faith" phrase, thereby invalidating the consecration, and the mass.
Second, let's assume the consecration is "valid" (which, is a big assumption). Does that mean that the mass is also valid? NO, NO, NO! To make such a logical jump is to forget the 3 PRINCIPAL parts of the mass - Offertory, Canon, Communion. The consecration is PART of the canon, and the canon is PART of the mass; THE CONSECRATION IS NOT THE MASS. It is a PART of the mass!
The N.O. "mass" only has 70% of the Offertory prayers of the true mass.
The N.O. "mass" only has 50% of the canon prayers of the true mass.
The N.O. "mass" mocks the purpose of communion, by "handing" it out and distorts it's purpose, its reverence, its nature because communion is meant to be sacred, an interaction between God and man, not a "supper" or a "celebration".
Conclusion: Even IF the N.O. consecration is correct, this means the consecration is "valid" (just as in a satanic black mass), but the Mass itself, which is a prayer, must have a proper Offertory, Canon and Communion for it to be VALID. If prayers are not said, if the ideas and words "sacrifice", "offering", "oblation", "priest", etc are suppressed (and they are, considering the prayers that were "cut out" of the N.O.) then the N.O. "mass" is not valid.
This doesn't even take into account whether the N.O. is LEGAL, which I argue that it is NOT. Nor is it moral, for many of the reasons stated above.