I've had nothing but good experiences with them.
I definitely recommend Mr. Rooter Plumbing of Long Beach. I've had them out three different times. They're more expensive than I probably would've gone for usually, but from the second they came to the door, I could say their price balances out with the service and customer service they provide. When they came, they showed me their identification at the door and put booties on their feet to protect my floor. After the service, they walked around and checked everything - drains, dishwashers, faucets, etc. - to make sure it was functioning properly. They even reminded me about a coupon I could use, which was great. I liked the fact that there was a guarantee that they explained to me. All their prices were laid out for me in a booklet, too, so I knew exactly what I was getting and what it would cost.
When I call, I'm able to speak to an actual technician. They give me their personal numbers, not just their work numbers, and send a little card after to ask how the service went. This way, if there were a problem, the customer would be able to tell them and $@!#% it in the bud.
I've used Mr. Rooter for things from casual jobs like drain clearing, to absolute emergencies where they came out immediately the next day. With everything, I've had nothing but a positive experience.