Here's my humble two cents.
Demand a Square D panel.....Homeline minimum, but a QO is much better (will run more money).
All of your knob and tube wiring should be reconnected through GFI breakers.
Make sure your electrician provides the newly code-required Arc-Fault breakers for all bedroom circuits.
Your voltage will not be 100v, you probably meant 100 amps. A 100 amp panel is the minimum allowed under code (as opposed to the older 60 amp styles). The higher the ampacity of your service, the larger the feeder wire required and the more cost incurred.
I can't speak to the cost of work in California, it's much higher than other parts of the country. Are you only having your panel upgraded?
Remember, the lowest bid is not always the best option. Thoroughly research your contractor before you hire him. How many years has he been in business? Is he a member of any local business organizations? What type of insurance does he carry? Will the electrician performing your work be licensed?