Many Anglo-Catholics oppose Mass and the Offices and make it their effort to stamp the offices out of the Sunday schedule so people come to mass instead. But while Holy Communion is undoubtedly the more important service of the two, it is wrong to oppose them to each other. Almost every knows that Cranmer's original intention was for Offices, Litany, and (at least) the Ante-Communion to make up the Sunday service. Most the classic Anglo-Catholic parishes I have known always offer Matins on Sundays, even if it is early and simply "said".
While MP and Mass are two separate services, the Offices help prepare one for Holy Communion, and are an excellent prelude to Mass. How? For one, the Scripture readings help bring out the meaning of the Epistle and Gospel from the Mass even better (almost like that old Protestant adage... that Scripture is interpreted through Scripture). I always study the Scriptures appointed for the Sunday Offices when preparing a sermon because they bring greater insight into the Gospel reading for that Sunday!
Here I should mention that some think that the additional Scripture readings are the only redeeming value of the Offices, and so there is created a "mongrel" service consisting of the 1928 Prayer Book with additional readings thrown in. But that is contrary to spirit of the liturgies, and makes a liturgy that is too long. Plus it ignores the fact that the singing the great canticles of the Church and the Psalms, and reciting the prayers of the office - especially the beautiful General Thanksgiving - are also critical parts of the service.
But the problem clergy face is this idea that God can only have one hour or so on Sunday... or that one can only attend one service on Sunday. This despite the fact that statistics show that the average "Facebook" user spends one hour a day on FB! Attendance at our Sunday Morning Prayer is anywhere from 3-8, even though it is a short (20 minutes tops) service, and even though a good number of parishioners live very close by. I am hoping that by having the organist play the service, and by preaching and teaching on it that we can increase attendance, and the reason I want the attendance to go up for MP is because it is spiritually beneficial, and as the service grows and we can do more with it - with a choir, etc. - that will help the church grow and prosper since the Offices are a "signature" Anglican service.