Value of the MSD

I totally agree with @Ricks70Duster340 about the ease of changing the advance springs. I have a 69 4 speed Barracuda with a 340 modified to about 375HP. About 5 years ago I bought an entire MS setup (6 Box, distributor, plug wires and coil). The difference was noticeable. Starts up way faster/easier, idles better and the throttle response is better.
Here is my $0.02 on why you buy the entire kit and not just the box:
Let's say you buy tires from one place and have the front end aligned somewhere else (I saw this all the time when I worked at Western Auto. Then, let's say, the guy comes back a month later complaining about uneven tire wear on the front. You tell him the front end is out, and the alignment place says it's bad tires. See where I'm going??? I always buy the whole kit from one place. That way I know that 1) All parts will work well together, and 2) There won't be any he said she said if there is a problem.