Its validity is doubtful due to many serious concerns. Read the Ottaviani intervention where he lists the theological problems of it. A catholic is not allowed to attend a mass/sacraments where validity is doubtful.
It is licit in that it exists, but not licit for a priest to use the missal (and consequently not licit for a layman to attend) because it violates Quo Priumum's strict requirements for exclusivity in the latin rite.
It is obviously immoral due to its circuмstances (sacrilegious communion in the hand, irreverent atmosphere, liturgical anomolies).
It. It. It. No regard to context. Go see the sung Novus Ordo at the London Oratory and I’ll give you a tenner for every one of “communion in the hand, irreverent atmosphere, liturgical anomolies” you witness.
How can a Catholic, seeing liturgical excellence that would have put most pre-60s parishes to shame, and knowing the orthodox beliefs of the celebrants (often more orthodox than Athanasian Creed denying SSPX priests), have any justifiable doubt as to the validity of such a mass? Is there something in the words of the Last Supper that is not found in the consecration of the Eucharistic Prayer? No, he can’t. That would not just be unreasonable but would amount to a lack of faith, hope and charity: faith in God to provide, hope in the reception of grace, and charity to not presume outwardly orthodox priests, who profess belief in the transubstantiation and sacrificial nature of the mass, are secret apostates!