Actually both are good at what they can do and in a mixed "Hybrid Modeling" envirnment SE does really well, look at
Sync is good for imported parts from other system and Non-sheet metal parts.
I don't use sync because my focus is sheet metal.
The area Sync really falls down is flat pattern controls and editing the gage of a material (Gage = Thickness and Bend radius)
Also w/ frames you have to make a choice early on. The Frame sections have to be either sync or ordered. I chose ordered.
Within a single part, you can do ordered work on top of Sync, but you can't do Sync work on top of Ordered. If this was the other way around I would be VERY motivated to use Sync.
I need the "basics" of my models to be ordered. Since I can't use sync on top of ordered, I don't use it at all.
From a conceptual standpoint, ordered maintains relations to creation sketches. In sync, sketches are used to start part creation, but once the part exist, the sketch removed.
If you need to have 100% control of your sketch you should use Ordered.
With complicated Geometries you have to edit the Sketch more than on time and this is guarantied with Ordered.
But I like and use Synchronous "with Sheet Metals too". Just in view cases for examples "Rail profiles" I used Ordered to be able to control every details and make controled changes.