Tradeoffs With Client Vs Server Side Postback Handling

I have a ListView that contains a large collection of rows with textboxes that users can optionally fill out. These textboxes are not databound. When the user clicks "next" i need to iterate over the rows and determine which fields the user has filled out, and then update a sort of "cart" with the data and move to a confirmation page ("you have selected a, g, v, zz, is this correct?" sort of thing).

I can think of two ways to deal with this. The first is, server side, to walk the items in the listview, get the control ID's, save this data to a list, then save it to a database cart table for the next screen to read.I can use jquery to collect all the values client side, then pass it back to the form in a hidden field and use something like Newton.Json to get the data into a similar list.What are the tradoffs of these two approaches?