The nice thing about building a desktop is that you have exact control over the parts. In addition if one part goes you simply replace it. Laptops are much harder to buy parts for, and you are stuck with what the manufacturer gives you. if you are doing video editing, there is only one way to go and that is to build your best desktop at what you can afford. Obviously building a desktop is twice as expensive, but it is your baby. You put the parts in and you know exactly what it does. Building gives you much more maneuverability and education and you will not be held hostage to the OEM replacement part by the manufacturer or hostage-takers on eBay.