Pick me is becoming popular in Colombo and relatively low priced and more reliable ( time of arrival) compared with other cab services based on what I experienced.
Anyone tried out Uber in Colombo?
This might be useful ( though the article is about 2 years old)
http://www.monitor.co.ug/Business/Auto/Who-owns-what-in-the-auto-industry-/-/688614/2272688/-/obfbfsz/-/index.html