How to choose a baby high chair? should I just buy the Ikea high chair?

It depends on individual. Whether it's easy to get your baby in and out is the most important concern. You'll want your baby to stay seated for a decent period of time therefore, need to make sure it's comfortable. Babies are notoriously messy eaters, and that means you need to consider how easy it is to clean up the high chair after a messy meal.