After Dropbox's security incident I decided to try out alternative services that were supposed to be more secure. I had heard of Spideroak before and I found Wuala during my search for a new service. Their advantage over Dropbox is that they both encrypt files client-side and do not have access to your data. The downside to this is that if you lose your password you lose access to your files. This won't be a problem if you use a password manager such as KeePass.
SpiderOak gives you two gigabytes for free while Wuala gives you five
gigabytes for free. Neither of them has the lan sync feature that
Dropbox has that transfers files between computers on the same network
internally. Instead they transfer files to their servers first and the
files then get downloaded to the other machines. This is obviously
slower and uses more bandwidth through your internet connection. They both allow you to sync multiple folders in different locations on the computer while Dropbox only allows you to sync folders that are under your main Dropbox folder.
Dropbox is probably the best known cloud syncing service. It is the simplest of the three mentioned here to setup and use and is the most reliable. Aside from the lan sync feature, Dropbox allows you to right-click on a file within your Dropbox folder and copy a link to share the file. It also offers two-step authentication which will prevent others from logging into your Dropbox account but still doesn't protect your data from Dropbox employees. Considering that their security incident was caused by an employee I have little faith that they will protect sensitive data and only use them for non-sensitive data like game saves. I have been using Dropbox the longest and have not once had a problem with the software. I was inconvenienced during a couple of outages but that was an issue with the servers and not the program. Deleted files are stored on Dropbox servers for thirty days and you can restore them from the website.
SpiderOak is the most complicated to setup and is slow to detect changes locally or on the server. Deleted files are stored locally on each machine and the trash has to be emptied individually. Sometimes the system tray icon doesn't load even though SpiderOak is still running in the background. This can usually be ignored but I like to see that changes are being synced. I have had a problem once or twice where the local database was corrupted and I had to run some commands to rebuild it. SpiderOak's support was helpful with this and responded in a reasonable amount of time.
Wuala is owned by LaCie, a European computer hardware company. Their servers are located in Switzerland, Germany and France. This is a plus to people who don't want their files hosted in the United States. Setup is more advanced than Dropbox but easier than SpiderOak. You can copy a link to share a file like with Dropbox but you have to do it from the Wuala client instead of an Explorer folder. It notices changes almost instantly like Dropbox does but takes longer to upload files. Upload and download have set limits, but you can set them above your internet connection speed if you want to maximize them. Wuala gives you the option of syncing multiple folders and using their client you can copy or paste files to a folder that isn't synced locally. Deleted files are moved into a Trash folder and emptying it applies to all computers.
I've had the most problems with Wuala. Sometimes the system tray icon doesn't load, but this doesn't happen as often as with SpiderOak. Wuala seems to take the longest time to load when the computer boots. It will often say file changes are pending and sit there for hours or days and never finish. Restarting the client or the computer may help but one of my computers has had pending for almost a week. I have had instances where I deleted a folder and it came back multiple times. I had to delete the files using the client, then kill the client on all of my machines and delete the files locally. A few times it has overwritten newer files with older files. It has also just stopped syncing a specific folder altogether and I had to delete it and recreate it. There is a bug with Wuala's overlay icons where Windows Explorer would refresh about every fifteen seconds which is fixed by uninstalling it. Wuala's support is rather slow to respond and not very helpful. Their support system seems to use German and the customer support aren't native English speakers so the language barrier is a factor.
Having said all of that, I believe Wuala has the most potential due to security and ease-of-use despite being written in Java. They just need to fix their bugs, add lan sync, and maybe hire more customer service reps including native English speakers.
I have been having multiple problems with Wuala and their tech support has been completely unhelpful. On some computers Windows locks up if you try to open an Explorer Window due to Wuala's CBFS. Newer versions don't fix the issue. I have had a ticket open for one pc for months that hasn't been answered. Others have been closed with a nonsense explanation. I wouldn't pay for this service and am switching back to SpiderOak.