From the blog Vultus Christi by means of New Liturgical Movement, ten reasons for celebrating the Mass, in either form, ad Orientem or versus Deum:
“1. The Holy Sacrifice of the Mass is experienced as having a theocentric direction and focus.
2. The faithful are spared the tiresome clerocentrism that has so overtaken the celebration of Holy Mass in the past forty years.
3. It has once again become evident that the Canon of the Mass (Prex Eucharistica) is addressed to the Father, by the priest, in the name of all.
4. The sacrificial character of the Mass is wonderfully expressed and affirmed.
5. Almost imperceptibly one discovers the rightness of praying silently at certain moments, of reciting certain parts of the Mass softly, and of cantillating others.
6. It affords the priest celebrant the boon of a holy modesty.
7. I find myself more and more identified with Christ, Eternal High Priest and Hostia perpetua, in the liturgy of the heavenly sanctuary, beyond the veil, before the Face of the Father.
8. During the Canon of the Mass I am graced with a profound recollection.
9. The people have become more reverent in their demeanour.
10. The entire celebration of Holy Mass has gained in reverence, attention, and devotion.”
Note that these ten reason are not ideological or philosophical but experiential insights, gained from actually praying with this orientation, juxtaposed with previous experience praying with the other orientation. Looks pretty good to me…