I have been burned a few times choosing a preety face WL. Generally, I'll be the same as you and choose a plainer girl and majority of the time, has turned out to be a great punt.

The hot ones know they are hot and sometimes won't provide good service. Not saying all of them are like that but speaking from experience. On a side note, my taste may be different to other punters so a girl I find hot, another punter might find ugly and vice versa.