I actually took CS M151A with Ercegovac.

The class was really tough, so it's hard to attribute the difficulty to the course material, his teaching, or a combination of both. I don't think any professor could make this class easy. Milos was a super nice professor, and although I never went to office hours he seemed very willing to help students; I think he would have been very encouraging and helpful if I had gone to him for help with the class.

It helps a lot to read the book before class. The lectures are basically a lighter version of the textbook (since he wrote it), and if you go in with an idea of what to expect the information he gives out is much more helpful. If you attend lecture without reading the textbook beforehand (like I did for about the last half of the quarter), the lectures are much more difficult to follow. The book isn't very exciting but it's straightforward.

I'd recommend him.