I have a Synology DS211+ (dual bay)
http://www.synology.com/products/product.php?product_name=DS211%2B&lang=enuIt has a Linux operating system, and is customizable. I have it set up to run Raid 1 using two 1.5Tb Seagate drives.
It's accessible from a browser window or from terminal. It also contains a whole host of software to extend it's use as a web server.
I haven't used it with Windows, but, it has the ability to set up Win/Mac/NFS.
The DiskStation software seems to be very well done. The only problem I had, when I first got the device, was with moving large (>3GB) files using the browser based DiskStation software without installing Oracle Java, but, recent updates to the DiskStation software (or maybe the release of java-1.7.0-openjdk) seems to have remedied that, so, I have no complaints at present.
All in all, I'm satisfied with Synology.