First, this really belongs to "toaru majutsu no Index" series, but since I never bought anything for that series, I'm categorizing it with its sister series.
Among the internet radios I listen to, this one isn't all that high up on my list, but I bought it because Misawa Sachika (of the Accel Radio fame) is the special guest. I heard her for the first time on Accel Radio, and my first impression of her was Koshimizu Ami. I mean, her voice reminded of Koshimizu Ami, and I could see her becoming more like Koshimizu Ami in the future, too. I'm hopeful, though, that Misawa will stay... cuter.
And the special recording only uses half of the audio CD capacity. For Y3,150, I expected more. Then again, since I don't even like it, longer wouldn't have made it better. I don't know why (or maybe I do), but I wonder if I would've liked it more if there were only Satou Rina and Misawa Sachika. Hey, I just realized "MISAKA" -> "MISAwa sachiKA," not that this has anything to do anything.
Among the internet radios I listen to, this one also has the most aggressively applied dynamic range compression. I noticed this on the broadcast radios, too. And this bad quality transferred right to the newer Railgun S radio.
Overall, I'm disappointed with this one. I doubt I'll pick up the volume 2.