Thanks. I only glanced at "7-sp" and believed Trek used a 7-sp cassette, not freewheel.
Freewheel hubs, by design, are more likely to experience axle breakage. The reason is that the hub bearings are located within the hub shell and rather close together, leaving a substantial portion of the axle unsupported. Stress from heavier riders, aggressive riding or impact can cause the hollow axle to break. Freewheels also thread onto the hub; torque from riding can make freewheels sometimes difficult to remove and replace for the home mechanic. There's also a limited selection of freewheels available in comparison to cassettes. Finally, upgrading to 8- or 9- speed (if you get that urge), will be too costly with the replacement of virtually the entire drivetrain and the rear wheel. While those may be negatives, keep in mind that there are plenty of people that have no complaints with their freewheels.
Another point you might consider is gearing. The 7.1 is geared pretty low. If you're towing a trailer or riding hilly terrain, then this may be of some use. You may feel your gearing is too limited for flatter, urban riding, however. Your current 7000 may have the same gearing, so that could be a point of reference.