I live in a zone where power failures are very common. While I was using EXT3 I lost data for several times due to power failures, and there was even a time a disk got corrupted.
After I switched to JFS the data lost is minimal and I never had a corrupted disk. Another think I enjoy in JFS is that its really quick to fsck a disc after power failure.
So is it safe to switch to EXT4 ?
The restriction on media files sharing only applies when using the built in Mionet client. I think the reason for the bad reviews is the slow speed. Although it has a gigabit interface, the processor doesn't have the required processing power.
The greatest transfer rate I can achieve using FTP is ~7MB/sec for reads and ~5MB/sec for writes.
But for it's low price and low power requirements I can't ask for more.