I had a live365 show called Consolidated Fuzz for about 4 years. The plan I was on cost about $15 a month and for that I think I got 300 MB which I was happy with because I only ever did shows that were a maximum of 4 hours long, so at 64kbps bitrate I never used up my allotted space anyhow. I was limited to 25 concurrent listeners on that plan. My total listening hours per month got as high as 1400, but average about 1000 I guess. I don't know if that qualifies as "succeeded" but I felt I did OK considering I did virtually no promotion for it.
The best thing is that people can search by genre and that's how I think most of my listeners found me.
My live365 show was basically an extension of my "real" radio show and what I used to do was compile a "best of" what I had played on radio every 3 weeks or so and leave that show up for that time. I don't think I would've wanted to get into programming hugely long shows because it is just too time consuming.
I was happy with live365 overall, just got a bit bored with it in the end. If I were you I'd try it out on a low cost plan for a bit. You can cancel anytime anyhow.
Incidentally yes 64kbps mp3s normally do sound horrible but on live365 they seemed to come across OK. If you want to upload higher quality you can, it just costs more.