I also saw this a few weeks ago and found it interesting at first, but in the end don't think I would pay extra for this. Donors are screened for some inheritable diseases anyway and this new test doesn't guarantee anything.There are still many diseases that they don't test for, there are spontaneous mutations that can always suddenly come up and then even more things that can go wrong like trisomies that you also cannot exclude with a test like this and which are a lot more common than the diseases they cover with this test.
With this test they look at your chromosomes and his, but that still doesn't mean that all sperm cells and all egg cells are healthy regarding this specific disease. You can have a perfect result and be a really good match and then the biologist picks a sperm cell for ICSI that coincidentally is not chromosomally normal.
Would you go to a geneticist with your partner/husband before starting a family? I would only do this if I had a reason based on family history. So if your family doesn't have a history of inherited diseases, there is no need. Donors are asked about this as well. (They could lie about family history, of course, but you need a little trust going into this anyway and you pick a donor that sounds truthful and authentic anyway, right?)
I don't know. I would much rather invest in pre-implantation diagnostics of the fertilized embryo if I was seriously concerned or wanted to avoid trisomies, because with this you know the status of the actual embryo.
You can never be 100 % sure. It is still biology, and biology consists of lots of coincidences and spontaneous events that you can't control.