I don't want to come across as painting everyone with the same brush. There are always exceptions. There will always be high time pilots who suck and there will also be low timers who rock. I just don't think that SIC'ing an RJ as soon as you hit 250 hours is a very beneficial way to acquire hours during those very early, formative hours of one's flying career. I really think that they are missing out on opportunities that will offer much more experience and knowledge that will benefit them down the road when they are competent to be PIC of an airliner.
It's nothing more than on-the-job training. Take a guy when he knows next to nothing, mold him to fit your company's pilot profile, throw him in the left seat and he's good to go. Take him out of that atmosphere though, and he might have no clue what to do. I just prefer more well rounded pilots.