An only child has the luxury of enjoying all the goodies by himself. There is no need for him to share anything as there is no one with whom to fight over the goodies. He usually enjoys first-hand products from clothes to toys to shoes. He has a room all to himself and can decorate it and mess it up any which way he desires.
On the flip side, an only child often experiences loneliness as there is no one lese, except his parents, with whom to play or interact. When he wishes for someone to play with or talk to, there will only be his parents.
Although he may invite friends over to his house or go to his friend's house for a game or chat, he has to contend with the fact that his firends may not be available to him at all times of the day. However, if one has siblings the latter are usually available twenty-four hours a day, every day. Furthermore, a child often prefers to talk to someone closer his age as he reaches adolescence. And friends cannot replace the camaraderie among siblingsd who grow up together under the same roof.
An only child will not know the joy of growing up with siblings. He will never understand the love despite all the fights among siblings. Perhaps one of the best experiences an only child will miss out on is the companionship, love and sense of belonging among siblings.
To conclude, being an only child has its perks, especially in terms of all things material. However, there are important experiences in life on which he will miss out, and all things considered. I feel it is better to have siblings than to be an only child.