It's a trade off. Rentals at Park Island are about half what mid-levels apartments are, with similar facilities and environment.
Many expats like Discovery Bay but may be ignorant about Park Island, which is a new project. At Park Island, the developer, SHK Properties, provide nice land scape and full club facilities, including an all-weather swimming pool etc. etc.... even a bowling hall. There are lots of units to choose from, all with modern kitchens, and some with balcony and more spacious kayouts.
Park Island is served by 24-hour ferry to Central at 30 min frequency of 20-25 min a trip. The pier is directly opposite IFC, in Central, just 1 MTR station away from Admiralty.