Heat and battery life will depend on you. The ROG is more powerful, so taken as a whole, will run hotter and not last as long. However, being less powerful, the Vivo, when really pushed hard in gaming will have a harder time competing with the ROG, consequently it'll run harder, hotter, and battery life will be shorter as a result. So depending on how much you use the laptop will determine its lifespan and battery life.
Low quality speakers in comparison to what? It's a laptop. It's severely limited as is for space, and speakers require a certain amount of room to work with. You won't get great sound from any laptop.
Choice? Which ever fits your needs. The ROG will be a better gaming experience on screen and will handle gaming abuse better, but could be entirely wrong for your aesthetics. You have to be able to type on it. If the keyboard is just not comfortable for you, whether buttons are too close or spring is not right, gaming is going to suck.
Speakers are the least concern, you can always Bluetooth an external, like a bullet or Beats etc and get far better audio than either laptop will produce.
So the question becomes, which laptop actually fits you better, in both needs and aesthetics