The vast majority of the people in コタキナバル are friendly and very few try to rip you off.
クアラルンプール is my favourite city in Southeast Asia so far. I love that there are so many trees around, and I really enjoyed the freedom of the subway and buses. It beats haggling with taxis and tuk tuks any day!
Staying for a night in コタキナバル made me feel like I'm in a place surrounded by odd people. They seem friendly at first, but after a while they become scary -- the way they stare, the way they move. It's like they want you drawn into their world and then cast spells on you that would make you stay there for the entirety of your life.
マラッカ … Driving in the city very dangerous. Roads are small.
ジョージタウン … Just go there and find Jim's Place. This friendly guy helps whenever and however he can. An angel in Georgetown -- also with excellent food, internet, and cheap accommodation.
コタキナバル … The only real good reason to travel here is to climb nearby Mount Kinabalu. And if you do, then don't book your climb through a middleman or tour company! Book directly from the company managing the lodge on the mountain, otherwise you pay too much. Having said that, the people are friendly. The price of a movie is only 8-11 ringgits ($3 usd). Plenty of places to eat (local & western chains). The bus system is cheap, but unpredictable. The taxis are a bit expensive -- one ride is the cost of a night at a hostel. There are lots of good, cheap hostels. The sidewalks are sketchy, dangerous, or nonexistent. It's not a good area of Malaysia for beaches or snorkeling.