First, let's get the basics out of the way. It's fully integrated into other Google products, and you get 5GB for free. If you're willing to pay for this service, you can upgrade to 25GB for $2.49/month, 100GB for $4.99/month, and 1TB for $49.99/month. If you go with an upgraded account, you'll get 25GB of Gmail storage, too. It'll be available for Windows and Apple PCs, iOS, and Android.
I've personally never understood the appeal of services like this. I'm old-fashioned, and would much rather carry the files I need around on a USB stick (or floppies before that). It gives me control, you can make it as secure as you want, and you're not dependent on the internet - a big deal when you move outside of the comfort zone of work-home-Starbucks.
Unless you're a hypocrite, you'll realise all these internet storage services suffer from a fatal flaw: a complete lack of privacy. SkyDrive, Dropbox, iCloud, and now Google Drive - there's absolutely no way to know what's being done with your data and who has access to it. There are privacy policies and terms of service, but in the end, they're only worth the paper they're written on. And they're digital, so go figure.
The big problem here is not that companies will inevitably use all this data to improve their products - there's some benefit to be had there for us, so that's not all that malevolent. What is problematic, however, is the fact these services operate out of the United States. And as little trust as I place in companies, I trust the US government even less.
The US has some frightening anti-privacy laws, and we've seen the extent to which the US is willing to go when it comes to things other countries would consider trivial. By storing all your data in the US, you're opening yourself up to a whole bunch of scary possibilities, and Apple, Google, Microsoft, Dropbox or whichever other US-based company will have no qualms about handing over your data to DC. I live in a country with well-developed personal freedoms, and from the top of my head, I can think of 5 things I've done which are completely normal and acceptable here, but would net me a hefty prison sentence in the US.
As such, it makes far more sense to look for local alternatives. Your local government is probably not that more trustworthy than the US one, but at least it's your government. You do have some form of control over them. Better yet, you'll be able to do something about possible abuse through your local court system, instead of being a foreigner in a US courtroom - a fate I wouldn't wish on my worst enemy.
If you really do need an internet storage service, I would be extremely careful about what you store in there, and gain at least some basic insight into things that might be normal to you, but are illegal in the US.
Better yet - set up your own internet storage service. In a broadband-rich country like The Netherlands, it's fairly trivial to set up your own always-on server with secure remote login (if you know of a decent software package, preferably open source, put it in the comments) to access your files. I have 120 MBit/s down and 10 Mbit/s up, without caps, and it's dirt-cheap - you can easily run a personal internet storage server with a connection like that.
In fact, this could be a pretty huge market: a simple and cheap plug-and-play device offering the same functionality as Dropbox or Google Drive. Open source, so you know what's going on. Secure and encrypted, so your stuff is safe. At home, so you know your data won't be abused. Local, so you don't have to fear foreign governments.
That would convert me to internet storage.