About Sailfish X: The "dual SIM" use case is somewhat rare: - people willing to have both personal and work phone numbers in a single device - people willing to use two different carriers (example: one for voice and the other for data) The only other reason to choose the F5122 over the F5121 is the internal memory (64 Gb vs 32 Gb). But if you use a cheap 64 Gb microSD to store all of your "large" (i.e. multimedia) data, you'll probably won't consider an issue having only 32Gb (Jolla1 was 16) inside...