I am trying to decide ... pros and cons ...

 

Do a "search".
Lots of threads on this very subject.

 

Matt Laidlaw answers some of your questions.
This review is for a 2017 model, but I don't know what year/years your looking at.
I've ridden both. I own a 2017 Heritage Softail Classic that I love.
However, if I were going to do a lot of interstate riding I'd go with a Road King.
A flat on the Road King's tubeless tires are easy to fix on the side of the road while a flat on my Heritage with its tube tires requires a tow to the dealership.
I have a pretty short inseam so the Heritage fits me a little better.
I don't know how tall/big you are, but anyone over 5'5" with a little leg strength should be able to handle a Road King with the stock seat and suspension.

 

I ride an 09 Road King. Love it! I rode my friends heritage and its ok but I think road king is a lot more comfortable than a heritage. However, heritage is cheaper! Lol

 

Every person that rides a Road King will claim it is the best. Every person that rides a Heritage will claim it's the best.

The 2018 Heritage redesign is a game changer.

Rent one for the weekend and rent the other for the next weekend.

There is a comparison tool on HD's website to compare specs side by side.

 

My vote is for the Road King.

 

As long as you match your purse, boots and belt...you're good.

JK, seriously - go drive them & decide. Who are we to size-up a bike for "your" riding enjoyment.

 

I like them both, giving up 7" of lean angle on the Heritage is a deal breaker for me. As far as price, the Heritage is the same price as the King, however, Factory Security and ABS are included. To add both on the King is another $1200.

 

I have been drooling over the M8 and know I will get one, it is just a matter of time. The RK keeps pulling my attention away from the other models. It will be the Road King for me.

 

OP couple questions to narrow the focus of your request:

You buying new or used?

Like a lot of people have mentioned, the new Softtails are a different animal from the 2000-2017 variety. 1999 and back are an entirely different animal as well.

Road Kings have changed as well

What kind of riding do you do?

Riding solo or two up?

Your size.

Answers to these questions will help you get better answers.