I used to use it, but when they added Exp. Share and then Audino's which are much faster ways to train up lagging pokemon, i stopped using it to gain levels, usually i would just dump 2 pokemon that i want to evolve for a pokedex entry in there and thats about it.
Once I got a poke to like level 70 or so with the moveset I desired and the EVs all set and they didnt learn moves anymore, i'd put them in the daycare, go to the subway station (BW/2) or to a mudcliff with the acro bike (RS), and tape down the directional button and go to sleep.
craptons of exp
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