I love Hong Kong transport system. It's fast to move the huge amount of people on the islands, it's sensible distance (within really walking distance), and mostly, it's really efficient. Most of the people uses the MTR (ours is MRT) and buses. However, if you are travelling with a huge luggage from the airport via Airport Express (train), and changing to MTR, the MTR may not be a good way. HK is upgrading their MTR exits, by placing lifts near exits with more hotels, but to search for one such exit may be more troublesome than just lugging your huge luggage up all the many many flights of stairs.
The hotels that are in the Kowloon area are mostly accessible by a bus from the airport, Bus A21. <– This interactive bus guide even shows you the picture of the bus-stop (or rather the surrounding buildings) so that you can actually find the bus stops, since HK bus stops are actually just bus stands with labels and the passengers just queue up behind the pole, along the road. At the website, click on "Route List" on the LEFT, and then at the interactive bus guide's left panel, search for A21 and it shows you the entire route on the map. On the bus, when coming to stops, the bus announces the name of the more famous hotels near the bus-stop.
The cost comparison? By taking the Airport Express to Hong Kong Island, it cost HKD 100 per pax. Then you need to take MTR to where your hotel is. A21 cost HKD33 per pax, and if you check the position of your hotel with reference to where the bus-stop is and book your hotel accordingly, the bus-stop may be right in front of your hotel. It is more convenient to take the bus.
The time comparison? Both take about half an hour for each direction, although there could be traffic congestion on the roads at the Kowloon area during peak hours.
Please note that the most expensive way of travelling is still taking the cab. It costs about HKD 250 to get to a Kowloon hotel at Jordan area. However, if you have 4 people in your group, you may want to consider getting a cab so that you want a comfortable ride that deposits you in front of your hotel. Many cab drivers still only know Cantonese, so please print out the Chinese name/address of your hotel and show it to them if you do not know the language.
My recommendations? Bus A21. Rely on myself. No stairs.