They're not Toyota/Honda dependable, but these Mazdas will take you places. If the car has been properly maintained you can expect it to go another 40-50,000 miles without much issue, and up to 75,000 miles with some maintenance. Again, that is going on the basis that it has been properly cared for up to this point.
In all honesty, I'd buy a MZ6 with 75k over a MS6 with 75k. I say go for it.