I searched for weeks for a good description of the differences between the free and paid hulu options. By chance I found this on their web site. I could not write a better description myself so here is what they say:
“The Hulu Plus subscription service is the first and only internet video subscription service to stream full current seasons and a deep library of back seasons of hit TV shows from ABC, FOX, NBC, and more, in HD, to computers, internet-connected TVs and Blu-ray players, set-top boxes, mobile phones, and tablets, all for $7.99 per month. (To see a full list of Hulu Plus enabled devices, please visit: www.hulu.com/plus#devices )
There are three key areas of difference between Hulu.com and Hulu Plus subscription service:
Device access. Hulu.com is a free option for users who want to watch TV shows on their computers. Hulu is limited to the PC environment. Hulu Plus enables users to watch Hulu content instantly in HD (720p) to internet-connected TVs, Blu-ray players, gaming consoles, set-top boxes, iPads, iPhones, and many other devices. (To see a full list of Hulu Plus enabled devices, please visit: www.hulu.com/plus#devices )
Content. Generally, Hulu.com offers the last five episodes that aired on TV, while Hulu Plus offers all current-season episodes from popular shows such as Glee, House, and Modern Family, and full series runs (all episodes from every season), including The X-Files, Arrested Development, Desperate Housewives, Battlestar Galactica, Monk, Psych, Saturday Night Live, Law & Order: Special Victims Unit, Ugly Betty, Buffy the Vampire Slayer, and dozens more. Hulu Plus is also the exclusive source for the most comprehensive library of the Criterion Collection archive with hundreds of classic films.
Video Quality. Hulu.com streams in standard definition while Hulu Plus streams in HD when available.”
The description above comes directly from hulus web site at http://www.hulu.com/discussions/33.
home media guy.