I finally went and downloaded Joost 0.9.1, to find that it now starts up a bit faster and has a bit more content (no news to speak of, but at least one Sci-Fi series - although I could do without all the pseudo-americana and alternative sports), is a trifle faster but still does not support the Apple remote and still relies far too much on having a mouse and keyboard present.
Also, searching tends to time out a lot, and I'm pretty sure I don't have a bandwidth issue these days (my cable operator, out of the kindness of their hearts, upped my home connection to 10Mbps, and regular surfing is now about as fast as in my office...).
My Macbook isn't too keen on it either (the fans start almost immediately, even if the application takes a while to actually display something on screen), and the lack of a PowerPC version prevents me from running it in a corner of my 20" iMac's screen.
A lot of people are intrigued about getting something like Joost running on an Apple/TV, but I think that's still a way off. As long as Joost isn't in a state that makes it trivial to set up on a machine (any machine), hook the thing up to a TV and use it with a simple remote, it won't happen.
Sure, it's getting better, but it won't make much of a dent on my TV habits for now.