My 2 yr old, 20 lb, 30 in dd is in a boba and she loves it. She is so comfy that she will nap in it. We don't use the stirrups because she thought those were for jumping.
Ds was jealous, so he got to take a ride in it. He is 4, 39 lb, 42 in. He fit fine, but quickly lost interest when he realized that he was "stuck" and couldn't run.
Sorry if I haven't gotten back with anyone via PM. Still learning the iPhone app and not very "techy".