I prefer the Geo bcs the mvt is so amazing. OK, the 918 is cool, too, and the AmVox1 has it's own history. But the
Geo is a worldtimer unlike any other - outside of JLC. The AmVox is 50 meters, and I wouldn't swim with it, whereas the Geo Compressor is conservatiely 100 meters. I would do ALMOST anything in it.
The other thing to consider is WHERE you want to wear it - or, more appropriately, be seen in it. The AmVox is great for office/dress, whereas the Geo is what I like to call a "business beater" (you can wear it for office wear, but it can go anywhere - including a pool, the ocean, etc. I will say that the Geo's mvt, in my opinion, is more hardy, so it can take more of what you dish out.
I don't know if this just made it harder, but I would consider point #2 more than #1.
-Dean