not clocked, but a little hystereisis (10-50mV) is always welcome.
on the topic of clocking, i have only seen fast clocked comparators when used in applications such as ADC, where a bank of comparators is strobed at the sampling instant, and all the values are read in parallel.
in my application, I will probably disable or reset the comparator for about 50ns, but then i need it to be active for about 250ns while my signals move around. if they cross at 60ns or 299ns i still need to trigger, so flash ADC comparators aren't good for me. continuous comparator most likely, but i will add a reset/shutdown regardless.
are you're a comparator guy?