Arq is the tool you need.
> "No proprietary encoding of archive descriptions. No proprietary encryption or compression features that would make it complicated or even impossible to use other clients."
That makes it different and more usable (at least for me), even if its behavior isn't "Time Machine" alike.
A trial or a demo would be nice.
Not being proprietary is an advantage. Freeze is as simple as it can be.
I really do not know.
But it is not meant to be a replacement for a full featured backup solution like Arq. I think some people like it a bit more "low-level" and simple and that's what Freeze is for.