I own more than one of each model, and have used several more, and found a consistency in my comparison of them. From a practical, albeit still subjective analysis, I prefer the Empress' type action because it's slightly lighter and more responsive. However, when applying your good enough standard to the equation, it's a case of splitting hairs; both models are nice to type with and get the job done with nearly equal aplomb.

I still recall the first time I saw a FP, and how I had thought it to be one of the ugliest typewriters that I had ever seen, which of course meant I had to buy one (there's no point in owning pretty machines when you can't juxtapose them with more vulgar examples). Time spent using and studying the FP had a dramatic effect on my perspective of it; not only does it type very well, I now think it's a wonderful design, but only because of its exquisite subtleties. In contrast, the Empress is an audacious typewriter. It's big, curvaceous, and organic, which means its name is fitting: there is an aura of royalty about the typewriter that seems to demand fealty of its typist.

The Empress is also more delicate, which is not a good thing and brings us back to the subject of practicality: If I had to select one machine for its robustness and ability to withstand the rigors of professional typing assignments, the FP would get the nod.The reality is though that very few contemporary model comparisons limit themselves to a critique of performance. There are myriad reasons, often wildly subjective ones, which current buyers use to base their purchasing decisions on. 

No fear, the FP has long since won me over and I no longer consider it ugly. I'm still looking for a FP-S to complete my small sub-collection of the model.

Wow! thanks Repartee, you have shown me with the picture of your nice Royal FP, that it is also the very model that was my Grandfathers and, that now sits in a place of honor on my desk.
G pa put a lot of miles on this machine, with everything from correspondence and billing from several decades of a thriving country vet practice to recording and publishing our families genealogical history.
It does need a little cleaning and attention but, still stands at the ready in amongst all the Underwoods and  Smith Coronas that crowd around for my attention. 

I.den wrote:

Just today I was able to acquire this, an Olympia SM9 from 1969

Congratulations, it looks like a fine machine and one with an interesting keyboard, but it's not a SM9. What you have is a SM8. 
 

As promised--the type face.