Couple of points Ajari.
Maybe of no great relevence but one of the fin keels advantages is agility under power, particularly in reverse. If you have a look at the thread "Pilot House ??? " from yesterday you'll see the narrow passage I had to reverse Raven up to get out of the slip. Its probably about 40 odd metres and not much more than a single boat width yet with a fin keeler I can reverse straight out. It's as easy as reversing a car. Do that in a full keeler and Oh Mama ! They do not like reversing at all.
Our girl is a fin with spade rudder. If I had my preference it would be fin with skeg hung rudder. To me that is a damn near perfect compromise.
Obviously this is not a set rule but you will find that despite the full keel being slower than a fin this is often not the case when reaching under normal working sails.
At this point you start moving into discussion of ketchs, schooners and the like where theoretically they are slower than a comparative sloop but when you free her up a bit and slap on a mizzen staysail the ketch picks up her skirts and flies. Same applies to gaffers. The speed than an old full keel gaffer can achieve when on a reach can be quite surprising.
"Do you think God gets stoned? I think so... Look at the platypus." Robin Williams.