Draft2Digital (D2D) and audio

I’ve just been updating my novels at D2D - back and front of book, covers, the giveaways etc - and the team got back to me offering to turn some of my books into audio books - for free! They take a royalty percentage.

Has anyone here used their system to make an audio book? Is it a reasonable audio? I don’t expect perfection from a free offer but can I expect a tolerable effort?