I ran another test of the 16GB A-Data class 6 SDHC card... this time there was trouble. I updated to v1.04 firmware, did a fresh format to the SD card, and set it to record at 24/96 with 1GB splits. It recorded 4 files ok then when it split to the 5th file, it stopped recording (there is only 1 second recorded for the 5th file). Unfortunately, I did not witness what happened when the recording stopped. I went to check it and the unit had powered down (assuming it sat idle for 3 minutes - as that is how I had the power save setup). I started recording again at it appears to be doing fine.
I guess I'll be repeating this test a few times.
Update: So the recording continued fine until the batteries ran out, and the last file is ok, so I assume it saved it before completely shutting down. I was using "Kirkland Signature" alkalines (Costco house brand) and got 4 hrs 4 minutes recorded before it shut down. The 5th file that it stopped on as described above seems to be missing file header info since I can't get any file properties when downloaded onto my computer - not sure what this indicates, whether there was a "slow card" error during recording or not.
I just got done testing a 16GB A-Data class 6 SDHC card. Ran it using a fesh pair of Energizer "standard" alkaline batteries. Card formatted on the r09hr. I got 5 hrs 15 min at 24/96, appears flawless, even stopped/started 4 times. No "slow card" errors. I haven't updated, so I'm running v1.03 firmware. I do the same with my PNY 16GB class 6 SDHC card tomorrow.