Someone could do a lot of math here to figure out how much average extra damage Cleave and WS gives over a standard adventure, but the result would probably be close enough to the same number that it really wouldn't matter a whole lot. (although I suspect WS would be a little higher).
The important thing really should be to decide if you think your character would like the "cool points" of getting the cleave, would like to go for a further WS chain feat to deal even more damage per hit, or perhaps branch off into another direction and do something else (Blind-Sight for lack of a better random choice).
Personally I would go for Cleave, just so you might have that once chance to save the parties bacon by cleaving and killing two big bad guys when everyones back is against the wall.
DS