Sit me up chair or exercauser?

Ka

Whats the difference between a fisher price sit me up chair and buying an activity center/exercauser? I want the sit me up chair to help him sit up but I feel like if I just wait and get an exercauser instead it will be worth the money. Seems like the sit me up will only last a couple months until he can sit up on his own. What do you moms prefer? My son will be 2 months next week and is starting to want to sit up.