They don't make it easy!
The iPad (and most tablet-y devices) has apps that will let you stream Netflix, Hulu, and Amazon Prime without any problem. I currently have a Netflix DVD subscription, so I wondered, what would I be missing if I switched to a streaming account? What would I be gaining by switching to Netflix streaming, versus buying a Hulu Plus subscription?
Long story short: it's impossible to say.
One question was easy: what would the price difference be? Click "Your Account and Help" in the upper right-hand corner, then under "MANAGE ACCOUNT" click the "Change Plan" link to see all of your options. I'm currently paying about $18/month for a 3-at-a-time unlimited DVD subscription. A Streaming subscription is only $8/month, and I wouldn't have to constantly be fiddling with my queue, driving to and from the post office, and managing my media consumption to deal with the mailing delays.
Beyond that, it's hard to say. Netflix used to have a very integrated website. They had only one page for (say) Arrested Development, and you could either stream it or queue up the DVDs. But that was back when the Streaming service was new, and they were promoting combo accounts.
There is a lot of content on Netflix which is only available for streaming, or only for DVD, but not both. I started with a simple question: was Arrested Development available for streaming? Hulu Prime has all three seasons available. They make it pretty easy for you to see this fact. Netflix? Not so much.
If you don't have a Streaming account, there doesn't appear to be any way to find out if something is available for streaming or not. If you log out of Netflix, go to the main page, then scroll to the very bottom and click "Browse Selection" you can look something up to see if Netflix has it. But they won't tell you if it's streaming, DVD, or both.
This leaves me with only two options: be a pest and ask my friends with Netflix Streaming to check availability for me, or just take the leap and switch to Streaming. Netflix doesn't really seem to care either way, frankly.