Galaxies are my primary area of interest, and I went with a C11 Edge HD after considering basically every scope in the 10-14" aperture range. The deciding factor for SCT over RC/Newt/DK was that I didn't want an open tube design where dirt and insects could easily get onto the mirror. I lived in Lubbock, Texas at the time (east of you), which has a very windy, dusty climate. I am happy with the light-gathering and detail-resolving capabilities of the Edge HD, and I plan to continue using it on galaxies.
Here are some insights gained from experience that might be helpful:
1) I ended up buying the 0.7x reducer because I had a lot of unforeseen problems running at f/10, and not the obvious one (guiding). I am still oversampling at f/7, so I did not lose any resolution. I do not plan to go back to f/10 except maybe to image a small PN at some point. I think oversampling is the way to go if you want to use deconvolution to sharpen up tiny details in galaxies. Just my opinion.
2) At higher focal length, you'll find yourself waiting for nights with good seeing. Keep the shorter focal length 'scopes for the rest of the nights.
3) Long subs and large aperture can conspire to produce bloated stars with unpleasant color distortions. In order to bring out the faint, outer arms of most galaxies, a very aggressive stretch is needed, which can absolutely ruin the stars. A large fraction of my processing time is spent "working on" stars, often by combining two versions of the image with different stretch characteristics.
4) Going for the closed tube design was a good decision, but if you live in a humid climate, dew and frost on the corrector plate of an SCT will rapidly ruin an imaging session. I think you're OK in El Paso (on most nights) but I lost some good nights to dew problems in Lubbock....
5) People with 14-17" astrographs will produce images that blow away the best image I can get with the 11" SCT. However, I can take my 11" SCT in the trunk of my car to a dark site. I am not a retired guy who lives at his pristine dark site and has an observatory (yet). Light pollution is bad news for fainter galaxies, and narrowband filters aren't going to save you.