I have a legacy system that uses JQGrid and it's a pain because the docs are lacking but it does work. We do saving via a 'SAVE' button using jquery and the dirty-cell function of the grid. This creates a string which is parsed by the controller and does an insert back into the DB. There may be a better way now, but that's what I inherited...
You can do drop downs and all sorts of things - there was an interactive example page on their wiki if I remember. --
