I've installed it on my computer, and Google Drive seems to function just like Dropbox. My preliminary impression is that the upload to google drive is super fast, and works every bit as good as dropbox for syncing files. One of the coolest features of google drive is what google does best: Search. After uploading a bunch of photos to drive, I did a search for something like "Sydney" and it returned a picture I took of the Bay bridge with the title. A search for "Brisbane" also successfully returned photos of the Brisbane skyline I took, and google even can recognize the "flatirons!"
Sharing files doesn't seem as easy on google drive as it was on dropbox. When I right click a file there's no option to share it, and the only way I can figure to share something is through the web interface, which isn't nearly as smooth as it was on dropbox.
You have the option to sync google docs, which don't take up any space on your google drive. This is a cool way to keep tabs of your google docs (and access them offline when you're traveling), however, if your google docs looks anything like mine, its super unorganized and full of a lot of stuff you don't want. Having it all in your google drive is annoying becasue there's no way to preview them on mac to easily sort through them. I have to open each one individually, see what it is, and decide if i want to keep or delete it.
The cool thing is Google drive is 4x cheeper than dropbox, for an almost identical service. That's something I can get stoked about, since i'm constantly pushing the limit of my dropbox allowance.
One thing I'll be really excited to see is integration between google drive and picasa, as well as google drive and google music. Full seamless integration between these services could really knock google drive out of the ballpark, although we all know that Google is notoriously slow to integrate their products.
Update: I now use Google Drive, Dropbox, and Amazon Glacier to back up my files, each for a different purpose. I still love Dropbox as my favorite syncing/sharing service, but I use google drive with my work account for sharing files within our network, and Amazon Glacier as a super cheap, emergency only, Fire-safe backup for photos and other stuff.