If I'm not mistaken bandar mahkota cheras is in bandar sungai long,right? For me, Bandar Mahkota is a good place to live in for middle-class. I got a friend who stay nearby there. That place are very cooling, developed and easy access road. Rental purpose, I would very recommend you if you're buying it for rental purpose. Lots of people who just got jobs and stayed there. But, I dunno about public transport. However, its in bad traffic after working hours if you're heading the area from KL. Hope this info is useful for you.