I was wondering the same thing and spoke to my friend, who is a drug rep for Allergan. This is what she told me:
The main difference between Vobella and every other filler is the technology that's used inside the filler. Vycross technology is used in Volbella. Vycross is also used in Voluma, which is another popular filler made by Allergan, that's FDA approved for restoring volume to your cheeks. The value of Vycross is that it is not hydrophilic so you can inject the product at 100 percent correction. Volbella also has the lowest HA concentration at 15mg per ml, which in theory should lead to less swelling. Voluma is 20 mg per ml and Juvederm is 24mg per ml. Vobella is a very spreadable filler. It's an intradermal injection on the lip. It allows you to inject in a more superficial plane to get an "air brush" effect. It's great for vertical lip lines. If a patient wants to enhance their lips, then they should use Vobella. If they want to augment their lips, they should use is Juvederm.