The only thing about all-in-one wheels I don't like is so much is proprietary with customized controller, unique battery, etc. If something goes wrong or the battery dies, you are dependent upon the manufacturer still being in business to deal with it (unless you are an electrician). And these businesses are not the most stable, even the big guys fail (bionx). Given the expense, a component system seems like a safer bet imo. You can still "swap a wheel" which has a hub motor, and the battery unit usually can be removed easily, but seems like longevity is more assured. Copenhagen wheel for example is super pricey, and is completely dependent upon them sticking around if stuff goes wrong.