hello, i will be staying at hong kong ovolo hotel aberdeen and will need 3 days of MTR service.

Hi, between HKIA and your hotel, airport shuttle bus no. A10 helps. Take it at HKIA and get off at Tin Wan Street, Shek Pai Wan Road. Then you can easily walk to your hotel.

Considering this, you don't need to use Airport Express train. Then a regular Octopus Card can be a good choice and it saves you money. It can be used on buses, MTR and ferries and you can enjoy some discounts.