I would rather you heard this from a client than from me, and I am collecting those words now. In the meantime, here is what I think you would hear.
That I am easy to work with, and that things get picked up without needing to be chased. That I ask good questions early, keep you in the loop without adding to your reading, and follow through on the small things as carefully as the big ones.
Mostly, I think you would hear that the difference is not really about hours saved. It is about not carrying the whole list around in your head any more, and knowing that what you handed over is actually being looked after.
If that sounds like the kind of working relationship you are after, I would love to hear what you are working on.