Here is my opinion...

First off, forget equipment. Bid what gives you the best qol. You will find that is all that matters. You have a few choices. If you live in a base, obviously I would say bid it. It will give you the best control and flexibility over your schedules. Additionally, you can pick up open time with little notice...something that you couldn't if you commute.

When bidding equipment, know that everything pays the same first year. The ATR in many cases is a quick way off of reserve. After your one year seat lock you can bid over to the jet for higher pay, or stay on the ATR until you can hold a line on the jet.

If you are bidding into a base that does not have the ATR, or absolutely refuse to fly it for whatever reason (SJS, aversion to French people, etc)...my opinion is to bid the Embraer. It is the largest fleet type in the company. This means you have a better opportunity for movement, schedule control, dropping trips (although don't hold your breath), open time, etc. You may be on reserve for a while, but not nearly as long as you could be on the crj. If you bid the crj, just know that you can't decide you don't like it and bid something else. You can bid up from the ATR, but not between jets. Also you can not bid from the jet to the ATR.

The crj is a great airplane, but not a logical choice unless you live in a base or just don't care about eternal reserve.

Hope that helps some.