This question is very much like asking whether a speedboat is better or a ship is better. Many people argue that C is faster, that is just like saying speedboat is faster. I have no experience in embedded system but my guess is C would be better for it. C++ is designed for big system and you simply won't get the real benefit if the system you are developing is small. For big project, C++ is always a better choice, once you know C++, it's not difficult to switch to C if you need to, the other way round would not be so easy. So, a speedboat is certainly faster than a ship for short distance, if you have to travel far, you would probably need to tie a really huge petrol tank behind the speedboat in order to travel long distance, and it sure will get really slow.