Nice to have the option, but unless I'm purely there to crash during a layover I'd rather take something downtown near the Taoyuan MRT, or the Novotel. Getting there/back is super inconvenient with the shuttle situation (and not too many bus connections), and the 20-30 minutes you'd spend waiting for the shuttle and getting there is most of the way to downtown Taipei on the MRT anyways. There's not much around the hotel either besides a few convenience stores.