I bought this to use as a booster seat for my 2 year old. The seat is very sturdy and hasn't moved since I strapped it to the seat (cloth seat).

I don't use the tray so I can't comment on it.

My son loves his new booster and enjoys sitting at the family table for meals. My son is a big kid (nearly 20kg) and he is very comfortable with plenty of room. He loves doing up the seatbelt.

Overall we are very happy with this purchase.
Sturdy, wipe clean, portable