For me it's not an either/or thing. Working on my relationship with myself and my relationship with my T both complement each other.

Also, actually having an IFS therapist is a little different than doing "inner child" work on yourself, IMO, because you have another person there actually guiding you through the process. I think when "inner child" work fails it's because there are other "parts" of ourselves that get in the way. For example, there might be a part of you that desperately wants to not be needy so it tries to get all the "needy" parts to shut up and be quiet. The expertise of an IFS therapist is helping people to untangle these kinds of conflicts. Also, I don't think a good IFS therapist would consider the work to be complete if the client was still unable to form intimate relationships or to trust and rely on other people.