I went out and signed up for the CrashPlan 30-day Trial a little over a month ago. I started by backing up about 350GB. (It didn't finish during the trial, but we - my family - have the lowest connection speed that you can get and still pay money for it. We get a max of 850 Kbps [+/-50 Kbps] up and an average of 1.1 Mbps down.) After the trial, my family decided (on my recommendation) buy the 4 year family plan. The family plan made much more sense than anything else because we have 5 computers in the house that need to be backed up.
Here are some CrashPlan features that I really like...
I have a lot of photos. More than 80 GB to be exact. The photos that I have are priceless to me (especially the ones of our trip to Vietnam and our recent cruise to Europe). Because of this, I wanted my photos to be backed up before my program files and the like. I was able to achieve this goal by creating multiple backup sets (one backup set with all of my important stuff and one with everything else) and setting the priority of my important stuff to 1. CrashPlan also allows you to set other things such as backup frequency.
As I mentioned previously, my family has the worst internet available, so when backups are running, our down speed suffers greatly. There are a few solutions however, one is to set the backup to only run between certain times (such as 22:00 to 06:00). The other method is to "sleep", essentially pause, the backup for a certain period of time. It is simple to do this too, all you have to do is right-click on the tray icon, click "Sleep...", and select how long you want the backup to be paused.
Backup to Friends
CrashPlan allows you to backup your files to a friend's computer. The best thing about it is that it's free. The backups are encrypted, so you don't have to worry about privacy. I, personally, don't backup to friends, but I have put this feature to use by setting up one of our old computers as a backup server. I attached an external drive to that computer and set CrashPlan to back up files to that drive. I then set up the other computers in my house to back up to that immobile computer's external hard drive.
If you have a mobile device that supports the CrashPlan mobile app (there's an app for Android, iOS, and Windoze Phone) you can access the files you have backed up to CrashPlan Central (that's CrashPlan's cloud backup location) from your mobile device. One catch though, you have to subscribe to CrashPlan +.