Recently, I am luckly enough to buy a Marine Big Date from a respected member in this forum. I have always wanted this watch and I am not disappointed at all after I get the watch, it is taking up a lot of my wrist time. As pinkpanther indicated, Rolex is famous for their sturdiness, I don't know if Breguet is as sturdy but what you are looking at is the craftsmanship that go into the watch, all the engraving in the parts, movement and all over the watch, that's why you need a clear case back.
ETA is just a mass produced movement, is it accurate and robust? I don't think there is too much complaint about it but what it lacks is the exclusiveness of the movement and the craftsmanship that goes into it. (same question as is a quartz movement robust and accurate?) However, many good brands are using ETA or modified ETA movement out there and by no means are their watches inferior. Enjoy your decision making process and let us know what you end up with.
Regards
Ivan