The G-Safe looks to me like any other external 2-fer in a RAID-1 arrary with the signal addition of the words "for photographers" attached to it. How is it better than any other external RAID-1 or, more importantly, than simple multiple redundant external single firewire (or eSATA) drives?
The problem I have with RAID-1 arrays is that while they might be "fail-proof" they're not really "fool-proof." Yes if one drive dies you have the other — but any OTHER problem that causes an untoward write or delete to the disk — virus, operator headspace error, you name it — does so, by definition, to both drives simultaneously, and there goes your data. On the downside, they double your drive cost and physical space requirements.
The way I've analyzed this is this:
The first goal of data protection should be not to lose the data in the first place. That means good hygiene practices and, it seems to me, RAID-5 for your live data. RAID-5 means if you lose a drive, you keep chugging along with no restore necessary. For those of us approaching a TB of data or more, that's important, as a complete restore from external HD can take hours and hours. (I don't even want to think about a complete restore from optical media!) RAID-6 would provide a little bit of extra comfort here, but that's a cost-benefit tradeoff that, at least here at the low end of the food chain, comes out better IMO in favor of RAID-5.
After that, you're talking about multiple redundant backups to recover from that catastrophic loss. At this point, yes a RAID-1 at each of the multiple redundant levels would provide some modest extra comfort over a single drive there, but less so than simply doubling the number of levels, which is also less expensive because those cool little RAID boxes aren't.
In practice, this means my live data (which, happily at this stage, is still ALL my data) resides on a 1.1TB RAID-5 in my main graphics machine. Downloaded cards get automatically duplicated to an external firewire drive, as they're downloaded, so I have at least two copies from the moment the image leaves the camera. The RAID-5 gets backed up, nightly and automatically, to two other external firewire drives (Seagate 400GB & 750GB). Those drives in turn get backed up every few weeks or so to their twins that live off-site (at my next-door neighbor's house).
Perfect? Of course not. But it seems to me that I've maximized my data security in the most cost-effective (and time-efficient) way possible. I'm subject to frequent lapses of judgment and insight though, so if I've missed something please let me know. (For example, I worry about backing up the backups *from* the backups, rather than from the live data, but I do that without deletes, so the backup-backups are larger than the backups, if you see what I mean. I think this guards better against the occasional stupid inadvertent delete on my part, which is probably the greatest threat to my data.)