I don't think you'll find a "statistical" answer. Most astrologers use the system they learned with; but there is some evidence that different chart natives do not respond identically to the same house system. For example, I didn't find that Warren Buffet's life matched well with Placidus, but it was a good fit with whole signs houses.
I read a lot of charts for people on this and another on-line forum, so I seldom see the person's appearance. Also, most of the questions we get don't so much involve a person's outward personality but particular problems they're facing.
Mostly I use Placidus, but I would use whole signs if (a) the birth time was only an estimate (like "around 1:00 pm,") (b) the person was born at a high latitude during a time of year when quadrant system (like Placidus) get really skewed, or (c) the person's life is well known, but Placidus houses just don't describe it very well.