Well, think of this question as building or buying a computer for example.
If you decide to build the computer yourself, it will feel more accomplishing and most likely cheaper then buying. However, if you buy it already assembled. It won't feel as accomplishing as building it and it will most likely be more expensive. At least, this is how I view this question.
However, people will also say SQI's in the market tend to be more expensive then making it yourself. This is because since the cards are already in this SQI's. They will be a tad more expensive then you would make them at. However, some also say if you make it yourself. It will be more expensive to make it yourself due to all the ingredients and cards.
In my opinion I think making it is the cheaper advantage though. Since I noticed when I made my tome from scratch. It costed me less zeny then it would have to buy it from the market.