We're flying into LGB for the first time on March 13, and we're so looking forward to it. What makes this airport appealing is everything the PPs have said -- it's smaller and the car rentals are just there, not shuttles to take you to the lots like at LAX.
Only thing to consider is if you have a flight that comes in later in the night. The car rentals close at 10:30pm, one at 10pm. With our flight landing at 9:45pm, it cuts pretty close.