After buying the Genuine Sony Mavica Discs™, and running into the same odd formatting troubles as the last disc, I managed to get it working... For the first couple of pictures. About ten pictures into the disc, it started taking longer and longer to save pics, with audible clicking and reseeking sounds coming from the drive
Recording videos became impossible, as that requires filling a small memory buffer and then writing it out to the disc in real time - the moment any substantial write errors accumulated, the video recording would error out, as the buffer was filling faster than it could write. Pictures would still save, but took upwards of 30 seconds to save... Not ideal, obviously.
Tonight I started testing the limits, and at 12 pictures finally had the disc error out for photos as well - totally unusable. Fortunately I can still read what was saved, and copy it all off over USB, but it's annoying to say the least that I spent extra on Sony media only for it to play worse with the camera.
I have heard the Sony media has all generally aged terribly - a common trend among Sony's first-party media, if you were a Hi8 user you know what I'm talking about. Though I have a sneaking feeling it may have to do with how I set up the media. I "initialized" the disc instead of "formatting" it. Formatting fills the entire disc surface with blanked bits, while Initializing only prepares the disc at the very beginning with basic file system information. Imagine the difference between a short and long format for a hard drive.
I've just put a Pengo brand 185mb disc in the camera and did the Format. After a few minutes it finished with no errors and appears to be playing nice, saving pictures in the expected five or so seconds.
So either the Sony media is just Bad, or it has to be formatted to play nice. Either one isn't great, but I obviously hope it's the latter. I'll have to test that later. For now, I'll be bringing the camera with me on vacation with the family. Hope to get some nice pics, hope this Pengo media serves me well! Bringing another blank Memorex disc if it doesn't tho.