In my 9 years total at two different regional airlines, I wish I had a buck for every time this question was asked.
I think every single regional was "the place to go" at one time or another. It was Comair about 6 years ago. Look at them now.
The point is that question is useless. The place to go now will probably suck in 5 years. None of the regionals are long term because of the whipsaw power mainline management has.
If I knew then what I know now, I wouldn't have gone to pilot school. This business isn't what it used to be and is still heading downhill. There is no job security unless you're senior at a mainline. And I don't know of any way to go directly to mainline unless you flew a fighter.