I've heard they've planned to offer more than 100 GB, but all in all, I think its far superior to Mozy or other alternatives, which I've used.
The peace of mind, knowing that my laptop can catch on fire, or be stolen, and I won't even loose a minute of work is very rewarding. With Mozy, I was always stressed, checking if my backup ran because I closed my laptop lid, or left it in the bag.
Besides, loosing even a day's worth of work is incredibly depressing.
Those new Mozy prices seem pretty close (if not cheaper) to what S3 will charge you, even for reduced redundancy storage.
The other thread quoted Mozy pricing at $432/year for 385 gigs. Amazon runs about 10 cents a gig for reduced redundancy, and another 10 cents a gig for transfer.
For around 150 GB of backup, you're looking at about $15 a month for S3 storage and another $15 to get the data from your machine to Amazon's.
Only if you completely fill your quota at Mozy. Most people don't have data neatly quantized into units of 50 GB ($6/month) and 125 GB ($10/month), so they'll end up paying the full price for less storage. In contrast, Amazon only charges for actual usage.
http://news.ycombinator.com/item?id=1946416
+
Other options, taken from there or elsewhere:
Carbonite (http://www.carbonite.com )
Crashplan (http://www.crashplan.com )
Backblaze (http://www.backblaze.com )
DropBox, Arq, others as mentioned already...
Hybir: https://www.hybir.com/
Amazon S3 (in conjunction with some services like http://code.google.com/p/duplicati/ or http://amanda.org/ or https://www.jungledisk.com/)
I didn't find a solution that matched my needs exactly when I found myself in your shoes, but at least there are a fair number of choices there!
I've tried restoring files without any problems.
Also, Diino are quite big and offer white label back up services to large companies like ISP's. This is good to note as it shows they'll be around for some time.