Dropbox. It's the Apple of Web storage companies. It's got a clan of fanboys who swear by it. And for good reason: It's simple to use and has some strong features. It's also one of the least flexible products among its competitors.
Holdouts (like me) who want the capability to sync files outside of Dropbox's walled garden -- the Dropbox folder on your desktop -- have to look to other products. Likewise, people who want to store or sync more than 100GB of files.
Personally, I've been using SugarSync, which does two things right: It lets you synchronize any folder on your computer (Windows or OS X) to its storage cloud and to your other computers. And it has storage plans that go up to 500GB, although they are expensive.
There's another way to do file sync, and that's to have your computers connect to each other directly (peer to peer) and synchronize when they are both online. The big advantage of peer-to-peer sync is that the technology provider doesn't have to pay for cloud storage, so it can be a cheap, or even free product. The disadvantage is that users can't access P2P files from the Web, and that two computers set to sync with each other have to be online at the same time to share files.
There's a good third solution: Hybrid sync, in which computers sync directly between themselves and also, optionally, to the cloud. Users get to choose which folders or files are stored in the cloud and which are shared between their own computers, and which get stored in multiple locations. Microsoft's Live Mesh (Windows and OS X) does this, and has for a while. And now there's a new player in this space: LogMeIn, with its new product, Cubby.
Cubby lets you sync any directory between multiple computers. By default, it also syncs directories to the cloud, so you can access them from the Web or from the mobile app (iPhone or Android). But you can turn off cloud sync for any folder to save space in your online account. Cubby, like Live Mesh, gives you 5GB of free cloud storage and an unlimited amount of computer-to-computer syncing. Prices for storage plans beyond 5GB have not yet been determined.
You can make any file public and get a link to it to share with others, assuming the file is synced to the cloud. Cubby also does file versioning for data stored on its servers, so it can be used as a backup service.
LogMeIn CEO Michael Simon told me that Cubby was designed around user security, but who doesn't say that? He did add, though, that within a few weeks, Cubby will allow users to use their own encryption keys with the service, so even LogMeIn won't be able to serve up users' files, no matter who asks.
I tried Cubby. It's very simple to set up, and connecting synced folders between computers was straightforward. Files update pretty quickly when computers are connected over the Internet in P2P mode. The iPhone app is clean, too. (I didn't try the Android app.)
In comparison, Microsoft's competitive product is a bit confusing; the product is part of SkyDrive (which has 25GB of free storage, of which you can use 5GB for syncing if you're using Live Mesh). The SkyDrive mobile app doesn't seem to pick up Live Mesh synced files and Live Mesh doesn't support versioning. If you can get past this, it is easy to use on desktops and laptops. But I'd be more comfortable recommending Cubby.
Simon thinks Cubby could do well against Dropbox, since LogMeIn has a large audience to market to. The company recently reported 14 million active registered users (1 million of which are paying customers). Simon said that file sync is the No. 1 most requested new feature from his customers.
Cubby is in open beta at the moment. If you sign up today, you might get online today, as reps there said they are now letting some people in.