for me , location or amenities will be my first choice to invest something in curent property market.
I think it's a good idea to buy property in those next upcoming hot locations such as Sungai Buloh, Rawang, Semenyih and Cyberjaya. Look at Kota Damansara and Ara Damansara now. Those days it was THE 'upcoming hot locations' and now they are so congested and property prices shot up. I regretted not buying a property from Ara Damansara back then when I had the chance too. Otherwise, I would've made great profit by now :( Now it's too late and it's too expensive for me.
I agreed with @Billy Law - location come first .. the location determine the rental income and rental increase holding power .And of course the appreciation ..
Some of the up coming areas are great on appreciation but not for rental market . However i personally felt MK still a good rental market ( i bought in MK too :D:D )