DARUKARU  No quarrels with the service, but I am noticing that the "bztransmit" program in the latest version (1.0.1.190) is suddenly consuming hundreds of megs of memory more than the previous release (build 162?). Right now it's at 350MB and climbing. Using Snow Leopard on an iMac5,1.  
(Version 1.0.1.190)

BOB T  Today, I switched from Mozy to Backblaze.

I have used Mozy for about 11 months.

I finally figured out that Mozy was causing extreme CPU usage and computer crashes.

Going through their outsourced tech support was a trying experience at best. I tried a beta of their latest release and it did not solve my problems. Their new release (to their credit) does not seem to be using near the memory of their prior product. However, it seemed to want to start all over with a new backup. I tried a restore of a single file from my account. Once I drilled down to the restore area, it seemed to take an extremely long time to download the data which would allow me to pick what I wanted to restore. It took more time for me to sign in to my account at Mozy prior to asking it to do a restore than it did for me to sign-in to my BB account and choose what I wanted to restore

In addition, this morning, after Mozy had about 12 hours to make a new backup, I had a message Mozy backup had failed!

I know it is not good to knock one product to justify going to another competitive product. I have no associations with BB of any sort.

What I liked, was that it quietly (CPU usage minimal) sat in the background to do it's thing on my Mac's HD. It allows you to backup your external drives if you find it necessary, and, it seems to be fast and efficient in responding to restore requests.

I am not associated in any way with BB. I advise anyone reading this to try both services (or even others) before deciding they will pop for one of these services.  
(Version 1.0.1.162)

DESERT CELT  Tried this application and really wanted it to work well on my Mac Pro. No dice. The developer's astonishment that Mac users seem to use a lot of "cloned backups" (external drives with SuperDuper clones on them) was a deal breaker for me and after more than a few emails instructing me how to "tweak" the program to make it work with my existing local backups, I cancelled my subscription.

Not ready for prime time on the Mac at least.  
(Version 1.0.1.162)

YOGI COACH  Earlier this year I did an in-depth review of online backup solutions for Mac - both for my own benefit and to provide recommendations to my consulting clients. I started putting Backblaze through its paces shortly after they added Mac support and have been using it ever since.

The software is well thought-out and works very well in my experience. I contacted their technical support department on one occasion regarding some messages that were appearing - I have a cloned version of my hard disk and, while all the data was getting backed up as expected, the software got a bit confused. The technical support was amazing and I had a workaround within 24 hours. Their software was updated a short-time later to address this issue and this minor inconvenience is now resolved.

I have 70GB of data backed up to Backblaze's servers, including all of my cherished photos, and sleep better at night knowing that my data is secure. Well worth $5/month (or $50/year) in my opinion. I have tried several restores and in all cases the process was intuitive and quick.

I highly recommend Backblaze.  
(Version 1.0.0.144)

SHOCKERSPAZ  In theory it looks great, and you cant beat the price. However I have noticed a troubling quirk... my Macbook Pro (circa 2008) hangs every few minutes when this app is backing up! Whats more disturbing is the fact that, after changing the backup to run only when I manually initiate them, I still had hangs throughout the day. Upon further investigation I discovered that the service was initiating backups on its own even set to "manual" backup only!!!   
(Version 1.0.0.134)

ZX  Not ready yet...Going back to Crashplan as usual!  
(Version 1.0.0.134)

GRIZZLER  I've used Backblaze for several months, and I love it. The key selling points for me were that 1) it backs up my computer in the background; 2) unlike Time Machine, it backs up my data offsite; 3) the user interface and functionality were better than Mozy's, which I also used for several months; and 4) the restore options are great, including the option to pay for overnight delivery of a USB drive containing the backed up data.  
(Version 1.0.0.134)

KITMOS  I beta tested this and wasn't too impressed and when I dumped it I had a hell of a time stopping it from reminding me that my billing had failed.  
(Version 1.0.0.134)