My opinion : keep both. The new smiles look more polished and I like some of them. The old smiles, however, should be kept. They have been here for so long that I miss them when they are gone eventhough I hated them at first.
I.E : :lol: is the old smiles whereas :lol2: is the new smiles. :-) is the old smiles whereas (-: is the new smiles, etc.