I feel the main advantage of Sepasoft is the database structure, and an object model to perform/save operations and track lots. You'll still do a lot of scripting. And if you're dealing with lots that may go negative (Qty < 0) because your physical qty/weight tracking isn't perfect, you'll have a few headaches.
You can easily compare the two, just install the Sepasoft modules and spend a few days trying to do basic tasks in it.
Please report back, I'd be glad to see someone reflect on this.