I can recall no less than five ditchings during my flying career. First was a Cessna 150 and both pilots survived (despite one having problems releasing his lap strap which had rotated on impact - the buckle was on the inside, against his waist). Second was a Jodel which floated - pilot survived. Third was a Twin Comanche which floated and the pilot survived. Fourth was a Jodel which partly sank. Two adults in the front got out but the children in the back didn't - and the pilot drowned trying to reach them. His wife was on the wreckage for about 24 hours before being discovered. Fifth was a Beech 24 which didn't float and the occupants survived.
I won't try to draw any conclusions from this - maybe they were all lucky - but the survival rate seems high if the aircraft gets down intact.