Uh, they have a dropbox-like client coming out soon. Also, I far prefer their web interface to dropbox's. I see no reason to continue using dropbox once skydrive client comes out.
The beauty of Skydrive is, it's WebDAV. You can mount it in Windows, you can mount it in OSX, you can mount it in Linux. There isn't a native client yet, but it doesn't strictly need one to work at a basic level.
Actually, again to make up for my inaccurate post, I have to give them kudos. I believe they're rolling out an oAuth api for SkyDrive so someone could build a linux client.
...unless you're on linux :)