I run this kind of setup on every one of my bikes, because I only use barend or down-tube shifters for the FD, and STI for the rear derailleur. The difference in feel between the two sides has never bothered me. The Dia Compe levers are old-fashioned, and the hoods are not very comfortable, the Tektro/Cane Creek levers are a lot comfier (Tektro and Cane Creek are the same lever except for the hood cover); Shimano sells some that look somewhat similar to the Dia Compe's so I would avoid them, although I've never actually tried the Shimano ones. The shape of the brake lever on the Tektro/Cane Creeks is awesome, and feels better than the STI brake lever, the Dia Compe lever doesn't have a great shape. I'm told the Tektro/Cane Creek hood shape is more similar to Campy than Shimano, but when paired with a Shimano STI on the other side, it feels fine to me.