We had the Fisher Price I think it's called Grow with Me high chair for my daughter. It is the space saver one that hooks onto a regular chair anyway. We took the tray off when she was about 10 or 11 months and pushed it up to the table to let her eat with us. Until recently this has worked out really well. She gets upset because the "arms" that hold the tray on while in use are still on the sides and it doesn't push all the way up to our table. I've tried moving them all around and I can't get her any closer. She is 21 months and for the past few weeks it has been a constant battle. She will say "all done, down please" and when we finally let her down she just wants up to sit on my lap and finish eating.
Finally this weekend we broke down and bought her a "big girl chair" aka a booster seat. We have made a huge deal and we even sing "big girl in a big girl chair, getting ready for ___ lunch, dinner, snack, playdough, etc." and she does the cutest little dance. She tells me everyday she loves her green big girl chair. So far just getting something new and a little different has worked really well for us. With Baby #2 just about here we were going to need to get her out of the high chair anway so that baby could lay with us while we eat.
We got the Prince Lionheart BoosterPod becuase it has straps that hook to the bottom and back of the chair, and has straps that strap the child into the seat. My little girl is a climber so this was important for us. It was the only one we could find that would strap her in and strap to the chair.