Cliff racers were mostly annoying in Morrowind. They would seemingly attack you all the time, and they had a very wide range of sight, meaning they would see you from far away and swoop in to attack you. Then often they wouldn't get into melee range and would just hover over your head while you swing at the air. Then there's times where you'd be swarmed by a flock of 4 or 5 of them and you had to wait for them all to get into range, kill them, wait for the next one, etc. It was just an annoyance.
That said, I didn't mind them all that much, but i know most people hated them.
I also had no problem with them except at very low level, an bow or an amulet with fire damage just enough to kill one solved the problem.
However if you had no ranged weapon they would be pretty annoying.
Remember the Morrowind advanced mod who added cliffracers with ranged spell attacks
