I agree with most of the above comments. I would like to add that what it may lack in the tension and suspense of Ring (was it that scary?) it makes up for in depth. What it pulls off well from the novel I thought was the portrayal of the time span. You get a real feeling of those seven days running out, thanks to the editing and a great leading actress (can't remember her name). Yes, it's a lower key version but stands up well on it's own. I felt as a remake this wasn't a waste of time.
If you like these movies I'd recommend the novel, and 'Spiral' is worth a watch.