Corner Cleaners at 140 East 19th Street, Costa Mesa, California.

The Corner Cleaners is the best laundering service in all of Orange County in my humble opinion. I found it by happenstance when I moved within walking distance. I have since moved away, but I drive over 10 miles to do any important dry cleaning or laundry with them. The top 10 reasons they are the best in Orange County:

10. They do laundering / dry cleaning on premises (this is a must)
9. If they can't get something out they will explain why so you know it wasn't overlooked.
8. Carla is the best, she will have your items ready by the time you walk in.
7. When your items are supposed to be done, they will be done a few hours early.
6. They understand what no starch means.
5. No missing buttons.
4. No charge for sewing on a loose button.
3. They are super gentle on wool sweaters, getting them clean without ruining the hand.
2. Affordable.
1. They deliver a true service, whatever is most important to you becomes most important to them.

Cons:
They are gentle with collars and cuffs, if you have a heavy ring you may need to pre-treat for them. Hardly a con.
They crease pants by standard. Which unless you are a 19th century aristocrat shouldn't be a problem.
Alterations are either good, fast, cheap; pick two.