It's advertising, but perfectly legitimate in the context. Many people in this thread are probably looking for an alternative now, so they might well be happy to see this mention.

Besides that it's also a personal story "I've been working on a competitor for a while and this is weirdly nicely timed".

A few months ago burtonator was under almost every article advertising his project ("Javascript? During the development of Polar Bookshelf (getpolarized.io) I have used Javascript!"), which I personally found a lot more annoying.

In the sea of close to 100% of pointless ads you quickly forget that they are actually supposed to make you aware of something you want. For many people in this thread that has probably succeeded.

Unless it allows you to own all your data - how it is different and what is the guarantee they won't be acquired in the same way and leave all their customers to look for a third service?

not all advertising is soullessly cynical