kkt
·X33 is vacuum and temp rated I thought. My money is NASA will stick with Omega. The bigger question is what is the back up in mars? Do you have a Martian day or earth day or both? Again modded x33 or similar is perfect.
Although the argument for pure mechanical is still strong.
If NASA decides to keep mission time in Sols, I'm sure Omega will make a watch that does too. As you say, likely a modified X33 that keeps Houston time as well.
But it'll be ages before we send a manned mission to Mars. That would require about six administrations and twelve congresses all keeping it as a goal.