Pro: REST API is the future of API, in 11 & 11.5 and the rest of the market
Con: implementation in 11 / 11.5 is about half that of OTA but catching up. Minimal working examples
For confirmation try searching for answers (forums / Google it) on anything REST and compare to OTA. Also ask a question in the forums re: REST. Not much luck for me to date but may get better in time.