Ok, but the way it's written up, it's not very effective due to the fact that he's being paid by the company whose products he is now so enthusiastically embracing.

I think it would look a little bit more genuine if there were a thing or two he missed, or something he's ditching for a product that doesn't just happen to be a Google product.

The real news item is not "Google employee uses Google products", but that Google is hiring a guy that seems to be well regarded and that MS, for whatever reason, let go, which most commentators seem to indicate was a smart move for Google and a dumb one for MS; but I guess he can't really say that himself without coming across badly.