I have been using Dropbox seemlessly now for about 6 months, and its awesome!

We use it at work all the time! Best part is that it works on Mac's and PC's!

I use dropbox literally every day.

I use it with clients to send files back and forth. It is very helpful in that sense because its very easy for clients to install and use and it works with windows and mac.

I also use it to back up projects that I am working on. When I have a new website to design I keep all my Drupal theming files in a folder and my Photoshop files and all images together so that I know they are on my computer and up in the clouds in case something happens to my computer. Its lightweight backup for me.

I even have a few small files hosting in a public folder that are streaming to a website.

I recommend dropbox to everybody for ease of use and reliability

Dropbox is great for quickly and easily sharing info with clients. A friend (that lives 5 hours away) and I are constantly sharing project files and this makes it 1000x easier than FTP or email.

Dropbox is great because it is automatic. It loses one star because it has a tendency to send files that you don't want it to send (lock files, backups, hidden, etc). When doing heavy duty projects that produce a lot of temporary files or any type of file that I want to be ignored in versioning I still use Subversion. But for something that anyone can sit down and use, Dropbox is your ticket.

Advantages

• It's free!!
• Automatic. No need for commit or checkout commands. No more forgetting to commit your changes. No more forgetting to update before editing.
• 2GB of free storage allows you to collaborate with more people without additional expenditure.
• Hosts public files. You can actually use Dropbox to create an automatically deploying website.
• Very small learning curve. If you can understand files and folders you can understand this product.

Disadvantages

• 2GB is enough space for many projects, but can start to feel tight when working on long term multimedia projects. Even if the project leader purchases additional storage this only helps if everyone on the project also purchases it.
• No way to ignore files. I keep mentioning this because it is the most annoying portion of this product to me. If you are using this for video editing, computer programming, MS Access/OpenOffice Base Databases, or any number of other applications, there can be tons of very large intermediate files that you don't necessarily want to be shared across the board. In fact many times things break when these are shared. This is a huge problem that Dropbox needs to fix!

Conclusion: This is a great solution for many, but not all projects.

It's better than LiveSync, Syncplicity, and even MobileMe! AND BEST OF ALL, it's free!
It's just like having a folder on your Desktop, and you just drag files in there, or create a new folder and it almost instantly (actually, I tried using the Windows 7 RC, it took about 5 minutes - WOW! Keep in mind that that is 3 GBs!) and you can DL it from any other computer! You start off with 2 GB of space and if you invite friends (which is not that hard, you can just keep deauthorizing your computer and put a new account and repeat) until you get 6 GBs of space! I'm sure that will be enough for most of you, but if you have huge files, you can pay around $50 a year to have 250 GBs of storage. And if that STILL isn't enough, get a $60 / year plan for 400 GBs of space! I have 6 GBs of space, and that's plenty for me! You can share files with friends simply by sending them an e-mail invite. It works great!

All in all, the integration with OS X and XP or Vista is seamless,(I don't have a Linux computer) you don't even have to open an application or anything!
Get this!