I Just replaced 12 vinyl windows in my 2-story house in Marina del Rey. After getting 5 other estimates, I went with American Reliable because they were the cheapest. Since we live in an old house, we didn't need anything fancy (cheap doesn't mean crappy).
Dealing with John M. has been a pleasure. At first, I thought he was just another smooth-talking salesman. But after the installation, they fulfilled every condition -- demolition, clean-up, stucco repair, walk-through. There were no increases in cost for unseen surprises, which some contractors might ad once you're committed.
The only mistake was that the bathroom window was not frosted. The glass will be replaced (it's in the contract). But surprisingly, John offered me a discount for my inconvenience, which I declined because I'm already 100% satisfied, and this is rare for me.
When they say they can beat most estimates by 5-10%, they mean it!!! People that are unsatisfied probably did not communicate there intent clearly, make things too complicated, or will never be satisfied. They should've looked or included any issues in the contract.
Whoever you go with, don't let some shnook sell you something you don't need, or create problems when there is none. Sears tried to tell me that the fire dept. wouldn't rescue me should there be a fire because my windows weren't up to code (4 inches too high). I told him that this house is grandfathered in with the new regulations. It's just another ruse to charge me an additional 1k. Can you believe it? And remember, window installation can be tricky, but it's not rocket science.