I used the RSCM Voice for Life for three of the four years I spent at my last position. The program basically involves a series of workbooks (light blue, dark blue, red, and yellow), that cover vocal skills, theory, and other aspects of basic musicianship. The books all have puzzles and other kinds of activities to drill new material, and In the back of each book is a list of targets each chorister is supposed to complete. When they finish them they're awarded a ribbon of the workbook color they just finished, on which to hang an RSCM medal.

For the most part I found that it worked well. But, I was able to split my choristers up into small groups and have each group come to a weekly session, in addition to the full choir rehearsal, to work on their workbooks and their targets. If you can do that it's great because they can learn the basic musicianship and vocal skills without having to spend a lot of rehearsal time on it. It can be a lot of work though and I'd recommend having someone to help out if you have more than a dozen or so kids.

One of my criticisms of VFL would probably be that they start going too fast once you get past the first level. You might find that in the second book the theory gets too complicated too quickly for kids younger than 5th or 6th grade, especially if they have no keyboard skills. There are also other things that you might need to adapt to your own methodology. For example, they expect the kids to be able to sight sing but don't really provide any kind of ideas on what approach to take. I just taught them solfege, and it worked great for me. Also, I had to supplement the workbooks with worksheets from Sibelius so that the kids could have some more practice.

Anyhow, if you can incorporate it well into a choral schedule and have enough help I would really recommend it.

PS-- I usually had the kids reimburse the parish for the workbooks, and we just paid for the teacher's edition and the RSCM annual membership.