I LOVE the small commuter jets! I take them all the time. Our direct flights to Orlando are on either 50 passenger or 35 passenger jets. They don't take long to load, there is usually plenty of gate room as they don't need a jetway (in otherwords, no back up when you land waiting for an available gate) and the luggage service is great!!
If you have a larger carryon and aren't checking luggage, they are still placed "under" the plane just like checked luggage, but a handler takes them just before you load the plane, then they are given right back to you at your destination gate!
No fussing with trying to cram large carryons in the overhead space or underneath the seat, and no waiting at baggage claim!
The only downside is if the weather is nasty, there is usually a small distance you have to walk on the tarmac that is uncovered, but otherwise, they are really nice!
Carol