Go for East, it will be easy for you to find a tenant. The price in East is 28-38 and in west it is 27 – 35 per sq ft depending on the type of construction and if the property is semi furnished or fully. Maximum of the new constructions are in West.
East Ghatkopar has better infrastructure than West Ghatkopar , It is closer to the Eastern Express Highway and thus enjoys a better connectivity to other parts of the city. Also the drainage system is better for EG, WG gets logged in monsoon as it is a low laying area. So I would say that EG is a better option.