Earlier this month, we reported that Joost, the ambitious P2P Internet TV service, had let its beta testers invite additional users. Immediately after its announcement, Joost was flooded with new users and then with complaints about the quality of the viewing experience.

We waited two more weeks -- long past the time Joost said its technical problems were fixed -- to try it out. The verdict: still not quite ready for prime time.

On the positive side, the user interface is simple and intuitive. The on-screen channel guide and controls, which can be made to vanish with a touch of the Esc key when you don't want to see them, are far easier to use than, say, my cable provider's VoD menu. Keyboard shortcuts are also available.

The sound is fine, even on low-end PC speakers, and the quality of the video is potentially fabulous. I found the small-window mode consistently good, and the full-screen mode occasionally outstanding -- much better than anything on my (standard-definition) TV.

But potential isn't actual, of course. On most channels, the full-screen picture simply isn't clear enough to watch. My guess is that this has to do with the resolution of the original files, rather than with anything related to Joost. Fortunately, it's possible to scale the picture by dragging the corner of the viewscreen, so you can watch any content on the largest screen that's comfortable to view, instead of being relegated to the 2-by-3-inch viewscreen.

A more serious problem is the stuttering of the audio/video stream, which is often annoying enough to deter anyone who isn't writing a review. I don't think the problem lies in my hardware (brand-new laptop, Intel Core Duo CPU with 1.66 GHz) or my connection (cable modem with 10 Mbps downstream, and I really am getting the 10 Mbps). Either Joost isn't scaling up its servers quickly enough or the P2P software still needs more tweaking. When you use P2P for downloads, interruptions don't matter; with streaming video, they matter very much.

The forum on Joost's site is full of advice about how to make the audio/video stream more smooth. Some of these tips and tricks may work -- I don't know. The point is that if Joost aims to be a substitute for TV, it has to be accessible to everyone, not just to the sort of people who enjoy updating the registries on their PCs.

The software is also a bit unstable. After the first time I put it into standby mode, I tried to turn it back on again and got nothing but beeps and error messages. (It wasn't me, honest! I didn't touch it!) I finally had to remove and re-install the software -- a procedure that produced still more error messages. But I persevered, and now the standby/restore function seems to be working properly.

Unless you read the FAQs thoroughly, you may not realize that even after you've stopped watching Joost you are still using enormous amounts of bandwidth, enough to get you a stern warning letter from your ISP, or worse. You actually have to close the icon out of your system tray in order to stop the bandwidth drain -- a fact that Joost will need to make clearer to users when it goes live.

Finally, content is somewhat less than compelling, unless you enjoy trivia contests about music videos. (150 channels and nothing to watch!) But once the technical issues are resolved and the number of users increases, I expect that we'll begin seeing more interesting content as well. UPDATE 5/22: Joost just brought in the Creative Artists Agency (CAA), the world’s leading talent and literary agency, to help it negotiate deals for "the most compelling and entertaining content." That ought to do the trick.

All in all, Joost is a welcome addition to the world of Internet video. And if all the stars align properly, it really could change the way we watch TV.