From what I here at Skywest is that the CR2 and CR7 are all in the same bid package, your seniority dictates what you fly. If you are on reserve you may fly both in the same day. The pay is the same at Skywest also. At ASA the pay is different and it is a totally different catagory. By catagory I mean you are either an AT7 (ATR-72) pilot, a CR2 (CRJ-200) pilot, or a CR7 (CRJ-700) pilot. The CR2 is comfy but the CR7 is comfy and fast. Our fleet breaks down like this:

The ATR is the "caddy". Its slow and big!

The CR2 is a Porsche Boxter. It looks fast but it really isn't!

The CR7 is a Porsche Carrara(sp?) 4. It looks fast and it is fast. No problem doing .82 at FL370!

But as Rick said they fly totally differently. The systems are not even that alike, IMO. CR7 has FADEC, CR2 doesn't. Different APU and limitations. Simplified electrical system on the CR7. CR7 has a much easier FIREX panel. The list goes on and on. From what I hear, Bombardier was really close on the number of differences for it to be a common type. A crew in Germany almost balled one up because they had been flying the CR2 for so long and got swapped in to a CR7 for one leg. The landings are completely different.

Sorry for the longwindedness, hope this helped.