The Customary is very similar to the American 1928 BCP, with the addition of collects for feasts that do not occur in the Anglican calendar, and of collects and short readings to make up the three day offices of Terce, Sext and None. sundays and feasts are provided with a long reading from the anglican patrimony: mediaeval writers, noted converts and anglo-catholics who remained in communion with the see of Canterbury. These readings seem well chosen give a good flavour of the contribution of the British Islands to the Catholic faith.
According to the rubrics, morning and evening prayer (matins and evensong) together constitute a complete office. With two longish readings they each take about thirty minutes to say. Compline and the day hours are provided if required. Compline is very similar to the 1928 BCP, with the ingenious addition of seasonal antiphons for the nunc dimittis (for which alternative canticles are provided at evening prayer if compline is to be said). Final anthems to Our Lady are also provided (in full rather than the truncated ones in the Roman Liturgy of the Hours).
The rubrics allow four readings from holy scripture as given in the lectionary, or one of the non biblical readings provided may be substituted on Sundays and Holy Days. Alternatively, the readings from the Office of Readings in the LotH may be used at either morning or evening prayer. Curiously, there is no mention of substituting the lections from the mass of the day, which would seem to make sense unless one is attending mass that day. The drawback is that to say the office one needs the customary plus either a bible or breviary (or missal).
Anyone used to praying the traditional Anglican office is unlikely to have difficulty with the Customary. It is slightly more complex than the BCP but easier than any version of the Roman breviary, largely due to the absence of antiphons for the psalms and canticles (though a welcome exception has been made for the great O antiphons). The psalms are read sequentially (except on Sundays when they are proper) and none is omitted, though, for the squeamish, 58 is optional (but, oddly, not 109). The Coverdale translation is used, with the familiar BCP canticles and collects, and we are permitted to say "Holy Ghost" and the traditional Lord's Prayer ("which art" rather than "who art" &c), for which much thanks.
Why do we need yet another daily office? The Customary allows members of the Ordinariates to pray the office from a volume with an imprimatur and therefore to pray with the Church. It uses translations from the Prayer Book with which many Anglicans are familiar and which are miles better than any modern alternatives, in an office that conforms to the modern Roman calendar. Other Catholic layfolk who are not bound to recite the office but who wish to do so in dignified heiratic English may also appreciate this book. Production values seem high - as they should for this price - and the non-leather binding looks durable.