As a matter of fact, age limitations are covered in many reviews of ours. As for car seats for 5 years olds, you should consider purchasing either a toddler car seat, a booster car seat, or a combination set which is a hybrid of both.
But if you truly are interested in our opinion and not just conclusions based on the summation of facts, we recommend purchasing a toddler car seat, namely, the Clek Foonf convertible seat. It the best seat for toddlers and infants, complete with perfect side impact protection.
Perhaps, irrelevant in your case, however, it is still a fact that the Foonf can be used in rear-facing mode until the child is 4 years of age. This is the main advantage this car seat has over others. The extended period of use is quite beneficial.