Here is what I have to say:
1. The combination of balanced armature earphones and acrylic shells do not cause shouty upper treble.
2. Never trust what representatives of certain companies/technologies say about competing companies/technologies.
NOTE: My review of the FitEar ToGo!334 is at TouchMyApps. My review of the Earsonics S-EM6 is at Headfonia.
Both earphones are good. Only one is great. That is the ToGo!334. What I love most about it isn't its sound, though it is very good; it is FitEar's incessant drive for perfection. Clean shells, clean wiring, strong cables, excellent use of both acrylic and titanium in the output tubes- these are tenets of the FitEar philosophy.
The S-EM6 is more moody, has lusher vocals, and, I feel, is more suited to jazz, vocalists, folk, and certain live music. It fits less well than the ToGo!334, has fiddlier ear pieces, and isn't made to the same exacting standards. Atomistically, I vastly prefer its moodiness for certain music. The S-EM6 may not be as clean sounding in certain frequencies, but it is more fun than the ToGo!334 for certain types of music.
But holistically, if I were to slap down +1.000- USD on an earphone, it would be one that inspired me from both a sound and a build perspective. Currently, ToGo!334 is hard to find. I hear from some people that it has a waiting list. The good news is that if you ever decide to sell it, you likely can recoup all of the costs. Those are the marks of a good investment.
Certain FitEar earphones hold their value very well. But if it came down to sound preference only, I'd probably side with S-EM6. That is personal. But my favourite Earsonics is the SM64. My favourite universal of all time is probably the Grado GR10, whose beautiful shiny body and clean, yet foot-tapping sound mates well with almost every of my favourite albums. It's also a LOT less expensive than the other two options.
As for CIEMs sounding shouty, they can. But that has nothing to do with balanced armatures. Ditto acrylic. It's part and parcel of the acoustic philosophy to which the manufacturer adheres. First: CIEM demos use universal tips for which they were not designed. Second: universal type earphones engage neither the outer nor the inner ear in the same way as customs. Demos will never sound exactly like the final products. They may, in fact, sound quite different. This is an unsolvable problem with CIEM earphones.
Finally, never take a representative of a certain company at her word. Her job is to convince you to buy the things her company make. And she will do her best to convince you that the technologies her company produce are best.
It is possible that they may be. It is just as possible that she is blowing wind up your ass.