I actually downloaded it this week and bought a license. It's really pretty cool, and one of few reasons I wanted to JB in the first place. Overall, it's fairly easy to use, although the documentation could be a little clearer; it took a bit of trial and error to figure out the right ways to do things. I watched the video on the website that Alex posted to see how to do everything, but the version in the video was different than the one I have installed. But I managed to figure it out within a few minutes of dedicated playing around.
Definitely worth it, as it gives you the option to stream or download podcasts to the device, which is nice. I'd rather download over wi-fi and listen on the go as opposed to streaming, but I can see a reason for both. I hope that in future FW releases, I can keep JB'ing because I could see myself getting used to using it.
Not as quick as pulling down from iTunes, but if you're on the go without your computer, and you want some new content, I doubt it can be beat. I tried the other ones on Cydia, and they were garbage compared to Podcaster. Totally not fleshed out.
If I discover anything else, I'll add it along the way.