Originally it shipped with a very imprecise renderer, with no basis on physical laws and really, really inefficient. For this matter, it was seen more as a toy, than a wannabe professional tool.
Then the Cycles engine appeared and all changed. It was the first open source implmentation of a path tracer, ready to be modified to one’s needs. Some companies saw its potential and backed the project with founds. Now the project is getting bigger and bigger and it is starting to be used in a professional environment. The bidirectional path tracer and the montecarlo extension are under development, so news are to be expected.
I made a little test render, with an Egyptian scene, to provide a sample of Cycles rendering engine powers. Here are the results (I know I am not very good at it, but I’m still learning).
My PC is only equipped with CPU rendering and, with a quality of 50 rays for pixel, render has completed in about 3 hours and 20 minutes. If you think you can do better here it is the blend file.