I think it depends on the type of floor. And let me complicate the question more with the fact that full soles come in a suede-like material or a hard leather. Most split-soles I have seen have suede-like soles.
Some hardwood folors are varnished, some are "raw" wood. Varnished floors are often slippery and full suede soles may be best. Raw wood, rougher in nature, in my opinion, require hard leather soles.
The "fabric" type floor coverings can vary tremendously. A new fabric can be very "stick" and hard leather may be easier.
Then there's the use of rosin.
What it ultimately comes down to is the type of sole that works best for you given the type of floor you're dancing on.
Sorry, no real answer. But I expect as you take more classes you'll see how different sole-styles will help your dancing.
balletboy[/i]