I am not exactly sure what specifically makes them "AV" drives, but they're designed for constant read/write (i.e. recording of video surveillance). Did you mean replacing of dead sectors with spares when you said error correction? (I am not aware of any ECC for HDDs) I wouldn't suspect that they would have any performance/feature negatives compared to a consumer drive, as consumer drives tend to be the "base line" and the more expensive drives build on these. Regardless of the reliability of the drives (i.e. even if you were using an enterprise drive) if you have no backup/redundancy of your data then the reliability of the drive provides a false sense of security. There is no one backup solution for everyone, but everyone should have one backup solution.
This is the part that refers to the "non-recoverable read errors per bits read, max". While I'm not exactly sure what this does, apparently a drive that has a worse value like the WD equivalent AV-GP series is more likely to leave you with corrupted data. For surveillance, an artifact is less critical than the drive going back and fixing the error and possibly losing frames. This info is very likely bad or misunderstood so anyone with actual knowledge is more than welcome for input.
Unfortunately I'm not yet at a point where I could afford full backup, but if this works out well, I'll probably sell some of my smaller drives to set something up within a year.
Is the SV35 a good drive? Yep! Is it likely more reliable than a standard consumer drive? Yep! (statistically speaking =P). Is it the right drive? Hard to say.
On a side note:
Anyone feel free to disagree with me here. Most drives you buy for general consumer use will last for many, many years (most MTBFs are well in excess of 500,000 hours if you like statistics). The main reason a drive will fail is if you have a "dud" and will commonly die quite fast (especially if you're writing to it a lot). This said, I don't really find a warranty to be overly helpful - I would obviously prefer a 5 year warranty over a 2 year warranty however I prefer a drive that has the right features for me - my drives are used for mass storage and are on 24-7 so I want low power consumption, and low noise. I love WD Greens for these reasons. I keep one drive (of 7) acting as a snap-shot RAID just in case something does fail.
I know the first year of a drive is the critical part and the longer warranty is mostly me hoping it has a better build quality, therefore reliability, but I can't help myself. Until I have actual backup, I'm aiming for the middle ground. As for other features, low noise is the only one that would be worth anything to me after reliability.
I don't trust Seagate...
I went with WD for several years and then tried my luck with a 1TB Barracuda. It died 1.5 years later due to bad sectors. It just started creating them one day and never stopped.
I know someone has probably had the same experience with WD, but it's just never been my experience. I've still got a 250 GB WD that's somewhere around almost 10 years old, and get's really extensive use.
I've only had 2 drives fail on me, an old 80GB Maxtor and a 640GB WD:
The Maxtor was probably going bad at the time as Windows would completely freeze if I tried to do anything in the first five minutes after logging on. My impatience put the final nail in that coffin and it hit me hard as it was the only drive I had at the time.
The 640 WD, just died without any warning in the first 6 months. I was copying some stuff at a friend's house so I left the room for a while (using it as an external usb drive). When I returned the drive was just clicking. The replacement is running fine ~3 years later.
I currently have a 2TB WD Green, which has developed some bad (3) and weak (3) sectors after some electrical issues (short version). I can't fix the weak sectors without formating and I can't format without a drive to move my data on. I don't have anything against WD in spite of my previous experiences since I know HDDs can go ###### up at any moment, but the reason I'm looking at Seagate for the next one is because of 1TB/platter (potential reliability again basically) which the Greens don't have as far as I'm aware.