They're small, crowded, and their rides seem bumpier. You have to gate-check your roll-aboard. What's more, crashes in recent years highlight safety concerns, that include allegedly young, less experienced, and poorly paid flight crews.
We have to admit seeing one or two RJ pilots who didn't look old enough to shave.
Because the Brazilian company Embraer manufactures such planes (in competition with Canada's Bombardier Canadair Regional Jets), flyers have given them the less than flattering nickname of Jungle Jets.
Yet more than half of all commercial airline departures in the US are operated by regional airlines, and we've flown on our share of them on flights as long as a couple of hours or more, ORD-DSM for example.
A recent article about RJs in USA Today is well worth reading:
Regional jets crowd skies, squeeze fliers
The title gives you the flavor.