Where should I buy my condo?

The first thing to ask.. is it for investment or for own stay? 

If it is for investment, let's take a look at the historical data:

Source: https://data.gov.sg/dataset/price-indices-of-non-landed-properties-by-locality

In case you are not familiar, here are what Core Central Region (CCR), Outside Central Region (OCR) and Rest of Central Region (RCR) includes:

Core Central Region (CCR): include Orchard, Bukit Timah, Newton, Novena, Tanjong Pagr, Downtown Core and Sentosa

Rest of Central Region (RCR):  Include Tiong bahru, Buona Vista, Harbourfront, Toa Payoh, Boon Keng, Bishan, Geylang, Paya Lebar, Little India

Outside Central Region (OCR) includes Clementi, Ang Mo Kio, Serangoon, SengKang, Hougang Tampines, Bedok, Changi, Pasir Ris, Choa Chu Kang, Bukit Batok, Woodlands, Yishun, Sembawang, Jurong.

We can see that from 2012 onwards, the price index in outside central region increases quickly, more than core central region n outside central region. 

One reason is also as part of the Government initatives and plans to decentralise Singapore, so that Singaporeans even in their heartlands can access to many shops and services. They do not need to travel all the way to town to get the things they need.

The Government also tired to plan regional and sub regional centres to outside the city, such as in Jurong, One North, Paya Lebar and Tampines in a bid to reduce traffic congestion to the CBD.

Thus from what we can see, the potential growth of property prices is Outside Central Region, where prices are now lower , but as more development, offices and regional centres are built, more people will go to work in these areas. This will result in demand for houses in these area, be it in housing purchase or rental.

Sources:
https://data.gov.sg/dataset/price-indices-of-non-landed-properties-by-locality 

https://www.straitstimes.com/business/property/acceleration-towards-a-decentralised-cbd-as-remote-working-takes-hold