DL is now flying regional jets into 97 of the 245 cities it serves and is the largest US regional jet carrier.

Reasons to hate RJs from the passenger/frequent flyer perspective:
- No chance at an upgrade. DL can now give unlimited upgrades to make Medallion members think that the program is improved, but with RJ service into 40% of its market (soon to be over half), the unlimited upgrades that DL started this year are useless and are a major hoax foisted on its most loyal customers (we'll give you unlimited upgrades, of course you can't use them because most of our aircraft, i.e. RJs, have only one cabin.
- Seating discomfort. It is torture flying in one of these planes. The bottom seat cushion is about a 1/2 inch piece of foam rubber on top of metal. And as with most other DL coach seating, the pitch is miserable.
- RJs are much noisier than mainline jet aircraft, sound as loud as 90 dB is routinely found in the cabin of RJs. Unions for AA flight attendants have raised this issue with American Eagle.
- No overhead bin space, must put "carryon" luggage in the back. Not only does this restrict what you can have in the cabin with you, but also leads to delays while waiting for "carryon" baggage to be unloaded
- Less experienced pilots. Certainly one of the reasons why airlines like RJs, they pay these folks less, but as the proliferation of these aircraft continues, I believe that it will lead to significant safety concerns.
- Low ceilings. Even those of average height can't stand straight in most of these aircraft. I am 5'10" and my head touches the ceiling of the Embraer 145. Continental restricts flight attendants on RJs to no taller than 5'9".
- In many airports, must climb stairs and walk outside on the tarmac to board these aircraft. An inconvenience to most of us, a major impetiment to the handicapped and ill.

Certainly many of the majors are making moves toward RJ rather than larger jet service; none more than DL. I suppose if all the carriers are flying RJs to a given destination and there is no choice, then there's no choice. But I will always choose to avoid a RJ is there is a choice, even if that means I have to fly cattle car Southwest over a cramped, cattle car DL RJ.