We're considering booking a 4 hour flight on US Airways Express. I was just wondering if there's really any difference between regional jets and regular planes. The flight would be on an Embraer 170, which seems very similar to a regular plane just with 2x2 seating instead of 3x2 or 3x3. Is this true, or will it be a horrible 4-hour flight?

Just a little smaller, and less overhead storare space. Your regular rollaboard or large duffle-bags will have to be gate-checked and not carried with you.

Regional jets are working their way into more and longer hauls all of the time because they're more economical to operate. I've taken flights of more than 1,000 miles on them already and I see more of those creeping into schedules all the time. In terms of speed and altitude, RJs don't really sacrifice anything. They're a little more cozy, of course (but in terms of your personal space that you are actually occupying compared to coach seats on a larger aircraft, I'm not sure that it's actually a factor. I think it's more about a "feel" because of having less open space in the cabin.)

Business fliers disparage them because they don't have business class seating. I fly with my wife and I like the 2x2 seating better than 3x3 where we almost invariably get matched up with an oversized rowmate.

As far as performance, I haven't noticed any difference, although I would imagine the smaller plane would be a little more subject to turbulence if they can't fly around it. Still, my roughest flight since leaving the military was on a 777; even the FAs strapped in.

Actually, some airlines do put first class seats on their Embraer 170/175/190/195 regional jets. It's just that USAirways don't.