i love this site. it's cheap and quick to receive DVD's and the watch instantly is great on my computer and xbox 360. the only bad thing is that on the instant watch they don't update it very often so it gets kind of hard to find something to watch, other than that it is amazing.
Netflix.com is a great site to get a nearly unlimited supply of videos in both streaming format, and sent to your house via mail. I have rated the site highly in all areas save for child safety. If a child were able to gain access to the site, (In most cases a child is far more skilled with computers than the supervising adult, so yes, it's very likely a child could EASILY gain access) they could be exposed to everything from nudity and lewd language, to violence, terror, and drug use. However, this is only my honest rating, and I do not feel it should negatively reflect the over-all usefulness and safety of the site. Besides, it is the job of the parents to keep their children out of harms way.
Netflix, while it seems to be a good company, have the tendency to rip you off with pricing. Also, if you sign-up for the trial and cancel, they will continue to bill you even though you canceled after your initial trial period.
One other note. If you download their title using a computer, you will not be able to burn the titles thanks to the draconian use of DRM, so you cannot watch the movie on DVD!