Don't get me wrong, I like the Embraers, but they feel semi-mainline to me:

1- In J, the cabin feels tight. Lets be fair, having a 1x2 feels a bit regional jet-like.
2- Overhead space is tight- most planes fit all carry ons, no problem. The E75 and E90 fit my bags, but barely, and they have all passed the Lufthansa carry on police (for size that is...not weight)....

they are 100x better than the CRAs, and in my opinion, far better than what UA and DL offer in comparison. That being said, they always feel a little "regional" to me, and I'd always prefer to be on an airbus, even though they are both mainline.

What seems strange to me is that express would operate a larger jet than mainline....Surely pax would prefer to hear "Air Canada flight XXX" versus "Air Canada Express flight XXX" Over the PA before boarding? When I hear express I imagine walking onto a DH3 or CRJ, skychecking my bag, having the FA do the automated safety demo, flying on a loud prop/rear-mounted jet, sitting in a tiny seat, and being thankful to get off! When I hear mainline, I think comfortable, spacious, relaxing, and nice!

In LGA or ORD, for example, don't you think business travelers would prefer mainline vs. express, in which case the E75 would be beneficial? Is this why most E75's are flown out east (YYZ-BOS/LGA/DCA/ORD) while the CRAs are used more in YYC/YWG/YVR?