They don't call it the King for nothing. I have had both and like the RKC. It has cruise control which makes a big difference once you get used to having it. I did like the Heritage and still have a ST Springer for tooling around the area but any real riding and I get the King out. YMMV
I think the touring rides better but the Heritage looks better...I have to go with RK...I would like to have a softail asa 2nd bike...Also my wife could ride it cuz it's lower....
By the way i don't own either. i have a Electra Glide Classic..added cruise.
The stock RK's can be a bit high for some of us, fortunately the fellow who originally owned the one I have had it lowered at both ends cause he was vertically challenged as am I so the lowered configuration has worked out for me also. BTW he bought a Heritage Classic.
I have both. both are 09's. (Heritage is my wife's bike). it's fun to scoot around on, but for any kind of riding longer than an hour I ride the king. she loves the heritage, it does feel more nimble, u sit "in" the bike rather than on it like the stock king (ive since replaced the seat and put the heritage style bars on the king and now it's great).
I'm guessing you probably posted this over in the Softie Section too for a balanced look. I'd be willing to guess that more than 80% of the Touring Folks have had or might even still have a Softail. There's a reason we all end up with Touring bikes. We enjoy the ride. The all day comfort, the variety of options, and the ability to carry all our crap. Decide what YOU want your bike to do for you, and then place your order. If I were in your boat, and actually didn't know which way to go (cause deep down usually we all know what we'd really rather have) I'd go out and rent them both, ride em both through the same area, and then make a decision. Good Luck, and let us know.
Seat height is a big diff. If your tall enough, 5'9" +, RK is probably the way to go. Also, depends on type of driving. around town - heritage
long trips - RK