Our son is the kind of kid asking me as often as he can to "show him something" on the screen.
Even at this age (29 months) he can sit still for a while and enjoy and have fun watching and hearing and seeing the words or dots or cars or whatever. This along with eating and playing with the children outside are his most favourite activities.
I think it depends on the kid's personality too, but usually they enjoy anything that's new and that uses many ways - visual, audio etc. What's more, when we do this together - watch the video by singing along, signing etc. - we have much fun.
In few weeks time we will have LR and LM. For now we are using YBCR. So, he's "old" too for these programmes!