Classic is fastest but yield less Megahits as to compare with Pendulum, take a look at this.
Pendulum
DP x 2= MegaHits
Classic
DP/2=MegaHits
Power=MegaHits x 4
My Daemon has 50dp, if use pendulum I get 100 MegaHits whereas using classic I get only 25 MegaHits. With pendulum it took me 35mins to do 100 MegaHits but slightly shorter with classic by about a few minutes say 25-30mins roughly maybe longer if the app crashes as it roll back my training.
Thing is bro it doesn't really matter which is better it all depends on one preferences coz at the end of the day you still making your digimon strong. For me im all classic but I do pendulum once awhile say when watching tv.
Read more: http://digimonunlimited.proboards.com/thread/2138#ixzz2leLxG1J8