Clubber, I've got one of those (I'm guessing it's the Addonics one, probably rebranded- looks the same)- they're ok, just plug into your router, setup is straightforward, but I had several issues.
Firstly mine only supported FAT32, not ntfs. Bought it about a year ago, so I'm guessing things have moved on, but it's worth confirming ntfs support.
It also crashed regularly, requiring rebooting maybe 2-3 times a week.
Transfer speeds aren't earthshattering- I couldn't stream movies reliably, and hd stuff was a definite no-go.
Don't use it anymore- it's not really a replacement for a proper nas setup, but costs bugger all to buy so may be worth buying to give it a go- it may work for you.
Google Addonics nas for reviews etc.