I've been MobileMe (.mac) customer since day one (iTools user before that). I have no plans of dropping the service anytime soon. However, for those that have no interest in all the benefits of MobileMe, you may find Dropbox to be a great alternative to MobileMe's iDisk for sharing files. Dropbox is by no means the first service to come along offering a free amount of storage space in the cloud. However, it's certainly one of the best I've seen when it comes to integration into the Mac OS. Like MobileMe, Dropbox is integrated into the Finder. Once you sign up for your FREE 2GBs of space (you can buy more if you need it), you can download their software, install it and then Dropbox becomes a part of the Finder. Not only will you have a Dropbox menu on the menubar, but you'll also see your Dropbox folder in your Home directory (or wherever you chose to put it). The beauty of this integration is that you treat your Dropbox folders like you do any other folders. You drag/save files to them as opposed to having to upload and download everything via a web browser. Once you put a document in one of your Dropbox folders it syncs to the cloud in the background. You'll also see these same documents/files/folders on any other Macs that you have configured with your Dropbox account.
Sharing is easy too
The main reason I use Dropbox is to share files with others. I can either share files on a file by file basis or I can create shared folders that automatically appear in my colleagues Dropbox folders. This is AWESOME! Just recently I setup a shared Dropbox folder so that the three of us could share various photos that we took on our last trip to Egypt. We each took great shots of the location but also of each other. This way I can easily share the pics I took of my colleagues and vice versa. If I choose to share an individual file with a NON-Dropbox user, they get a simple link to click on and download the file.
You can pay for more if you like
2GBs is not a ton of space. You can buy more if you need it. However, this is where MobileMe might have the advantage. We all know that we can get MobileMe for LESS by buying older retail packages or find sales throughout the year. You can then just open up the box and plug in the new code when it comes time to renew. For example, here's one from Amazon.com for only $53. (NEVER PAY APPLE's FULL $99/Year!). At this discounted price hat works out to $4.42/month and you get 20GB of space.
With Dropbox.com you get 2GB for Free OR you can pay $9.99/month or $99/year for 50GB. Granted it's more than double the space you get with MobileMe, but MobileMe offers more than just iDisk storage. In other words If I'm going to pay for one of these MobileMe works out to be the better deal.
Yes, Dropbox also has an iOS App to make it easy to access and share your files. I'm also seeing several 3rd party Apps that allow you to access or save files to your Dropbox account. It's really becoming quite popular. For example, I scan receipts with my iPhone's camera using the Scanner Pro App and once I save the PDF that it creates I can upload the PDF directly to my Dropbox folder from within the Scanner Pro app. By scanning and uploading these receipts as they occur it makes doing my expense reports a breeze.