I think it really depends on personal preference when it comes to location.
I lived in D 15 , but I do enjoy my 'excursion's up to Bukit Timah. Was over there for the weekend. The quaint little shops along Bukit Timah Rd are attractive and fun to discover, but somehow I still prefer the lure of the East.
To me , bukit Timah is more 'green' and more open than D 15 , but there is something about the smell of the sea in the east that appeals to me
Love the ride home from Raffles place. like the fate I can see a bit of the sea and the 10 min drive back home.