If you are looking for a beginner's instrument for your child, you should pay particular attention to a design that is suitable for children. It does not make much sense to buy an expensive orchestra xylophone for a small child who is just starting to get into music. Instead, it is probably much more beneficial for the child to start with a small xylophone of (depending on age) one to two octaves in range.
Like some of the models listed above, there are many xylophones with colourful bars. This is not a purely decorative aspect, but also helps many beginners to rehearse the pieces. The colours of the tones can be good thought aids when learning a new piece. For example, you can mark the note in red in the sheet music that is also red on the instrument. There are also sets available that consist of a colourful xylophone and an exercise book in which the colours of the bars are picked up. This makes learning notes easy and playful, even for younger children.