VistaMS
VistaMS is a Maple Story private server. Its exp rate 150x that of normal MS. Its drop rate is described with NA but you get an equip almost ever drop. I would say about 99% you will get an equip. It took me about 3 hours to get to lvl 94.
Silver Slime-in Maple Story=20,000 exp
Silver Slime-in VistaMS=3,000,000 exp
Silver Slime-in VistaMS=3,000,000 exp