I did this same route but connecting out of SAN for over two months. Out on Sunday, return on Thursday. I loved the mainline aircraft to ORD but after that, it just went down hill.

Skywest has brought the service up but the RJ is not my airplane of choice. That seems to be the longest 1 - 1.5 flight I've ever taken. And as you have found out, they are really full most of the time.