Both are showable, the non bearded seem to less common in show, the bearded is what you see more of.
The only difference is in non bearded they have more wattle growth, and the bearded have very minimal wattles and what they do have the beard covers it. The beard also can get rather messy when they eat things like watermelon, pumpkin, etc...
either variety with a large crest - the they dunk their crests in open water containers, and if it gets cold and they exposed to the cold it can freeze, which can be a bad thing. Silkies do not tend to do well with other breeds of birds because of their crests, and mild temperaments they are easy targets for being picked on, and their crests stripped, especially by larger breeds because one good peck on the head can potentially kill a vaulted silkie. Free ranging isn't too bad, but they really shouldn't be cooped up or penned together with other breeds.
Really it just comes down to looks, do you prefer the look of one over the other?