A well planned life is better than a spontaneous one, at least for me. Many people enjoy living their life spontaneously and would have it no other way. I am not one of them. I like to plan for the future and make sure I have the money and security to do what I want.
A well-planned life including goal-setting is an important factor when the quality of life is important. Spontaneity is good for fun, but when it comes to having a stable life with few upsetting surprises, planning ahead is a good idea. Emergency funds, getting past setbacks and dealing with circumstances beyond one's control are the keys to moving through life with few interruptions.
A spontaneous life can lead to a lot of bad things. You are much more likely to be poor due to bad spending habits. You are more likely to catch a sexually transmitted diseases due to risky sex. You will have to job hop as your spontaneous decisions will affect you poorly.
Yes, a well-planned life is better than a spontaneous one, because a person who plans their life can ultimately have more fun. A person who saves for a trip will be able to go on a trip. A person who spends their money hastily will not be able to do the things that they want to do in the end. A person who saves and plans their life has more security, so they have fewer things to worry about.
I do not believe a well planned life is better than a spontaneous one. For the most part, I don't think people directly ask themselves these questions, they simply choose a path and then realize looking back that it was either well planned out or not. I believe this is a very subjective decision and its value is determined by the person asking. Both can be equally worth while.