some say near mrt/lrt is good some say not good.
but for me near mrt/lrt is always an advantage.
Back to your question new property or existing?
assuming you have enough cash.
if you want immediate return then go for existing (can rent out for return)
else you can consider new property.

advantage if you stay (and need to use it). not advantage if you're buying for investment and the price is sky high.

i'm not sure if you notice area such as pdn indah/cahaya/cempaka/miharja is very easy to get tenant due to close proximity to lrt...
if you let out room it is even easier.
the price maybe is on the high side but the current market seem stagnant maybe ts can survey and get good deal