scotland rdtrip - commerical tour or diy tour

my wife and I will be catching the last three day of the fringe festival and then have 3 more days to catch glimpses of the rest of Scotland. So, my question is: Do I do a 3 day tour w/ a tour group, or do I rent a car and drive for 3 days all around Scotland?

and if the answer is a tour, what and who would you recommend? As for preferences: landscapes and some historical sites/ castles. Also, is going by St Andrews worth it?

thanks in advance!

If you want to stop when you want go by car.
If you want to be told where to stop go on a tour
If you are ok driving on the left go by car, otherwise go on a tour
Decide where you want to go and if a tour goes there consider it.
If you want to drive all around Scotland take more than 3 days.
Is St Andrews worth it. I think so but it depends upon how far off route you have to go to visit and do you have the time..
Sorry, not into recommending commercial enterprises.
Only you can decide.