We have Netflix with 2 DVD plan ($21.38 a month, I think streaming only is $8). Normally for us its a 3 day turn around. They send you the DVD in a mailer and when done I put it back in the envelope and put it out on the mail box.
Streaming: Not all movies are on demand. New releases tend to be DVD only Hence, I also have the DVD option. We have Comcast cable at the house and stream to the TV but at peak times (Friday 8 pm type thing) we have experienced buffer issues from Netflix.
My smart phone has a Netflix app so I can stream to my Droid Razor anywhere. I have a mini HDMI cable ($20? at Verizon) and can stream Netflix from my phone (4G Verizon) to my 32" flat screen in the camper using the HDMI input. I have a 8 GB shared plan and we normally average around 4-5 GB a month. We watch a couple movies a month this way and just keep an eye on my data usage.