CareerCup

UDP is connectionless. So the main thing that we miss is reliability.

While this is true - I'm not sure that reliability is the answer we're looking for. If one frame is corrupted - it won't affect the other frames - and the effect is negligible.
I think that ordering is the most important attribute: if the frames are being received out-of-order, they'll be presented in the wrong order - so you need a buffering mechanism or some other method above the UDP connection to prevent it.

I would say, accuracy or correctness, which includes flow control, sequencing, and error detection. TCP is more accurate than UDP most because it has flow control scheme. But UDP is much faster; it doesn't care if all the packages are sent in the right order or if they arrive or not. Thus, UDP is always used in streaming audio or video transmission (VOIP), and they don't have high quality.