Also, often to maintain the same flavor profile more tobacco has to be packed into smaller ring gauges resulting in stronger smokes. I feel there is a law of dimishing returns at work with this rule, so petit coronas and lonsdales don't really apply. There are plenty of exceptions too.
As for preferences, certain cigars I like better at larger ring gauge (52+) and some I prefer smaller. For example, I think almost all DPG cigars are at their best as a robusto (5x50), Camachos need to be larger, and I much prefer the larger ring CAOs (54+) to their smaller counterparts .
My default size for any unknown cigar would probably be a toro, and if I liked it then would explore larger or smaller based on my initial impressions.