First of all, I'd want to know who this Christian publisher is. It's a sad fact, but many Christians are deceived by scams that wrap themselves in the "Christian" mantle. (See our Bewares and Background Check forum for examples.) In 1 John 4:1, we are admonished to "...believe not every spirit, but try the spirits whether they are of God: because many false prophets are gone out into the world." So too, we should make sure that the publisher is really "Christian". Being a Christian does not mean being gullible.
Secondly, I'd make sure there is no fiduciary ties between the submission site and the publisher. This would represent a conflict of interest. Even for a legitimate publisher, conflicts of interest should be avoided.
Thirdly, I hate to sound cynical, but this sounds like an excellent way for a publisher to reduce its own slush pile by diverting novice writers to a place where they can be safely ignored. One doesn't like to thing of a Christian publisher doing something like that, but Christian businesses don't always act any more "Christian" than secular ones.
I guess the only way I would use a submission service is if the publisher said it was the ONLY way they accepted submissions. And then, I would do it only after I had submitted to every other market possible.
