I have never seen the jumperoos in use,
but I recommend an evenflo exersaucer. similiar to this:
Amazon.com: Evenflo ExersaucerŽ Mega Circus: Baby
The nursery I use to work for, as well as several families I've nannied for have the Evenflo exersaucers and they've held up great!b And all my kids have loved jumping in them.