Actually, there is no better or worse option here. This will basically boil down to your personal preference. If you are someone who loves to build things, then it won’t take much of your time and effort to create an RC car. It is easy and very rewarding, and by the time you are done with the assembly, surely, you will have full knowledge of your car inside and out.
On the other hand, those who cannot stand reading instruction manuals or using screwdrivers should go for RTR or Ready To Run. If you are a newbie and have no knack at mechanical things, then the RTR option is the safest way to go. RTR cars are professionally assembled and correctly set up; thus, no more screwdrivers and long instruction manuals.