I use all three firms in my investing. Here's my (subjective) view:
* Vanguard has the lowest expense ratios and gives you the best value for your money. I'm happy with the customer service. Only minus is that most funds have a $3,000 minimum.
* Fidelity has a much wider choice of funds than Vanguard's. Vanguard's isn't too shabby, but there is something for just about everyone at Fidelity.
* Schwab is a great brokerage. Lots of online help and resources. There are cheaper discount brokers but I don't know of any with such great service.
One additional consideration in these turbulent times. If you open a brokerage account at Schwab (or any other broker) and the firm goes under, you are insured by SIPC. However, SIPC is a private organization run by the brokers, NOT a federal program like FDIC for banks. If there were a major meltdown of brokerage firms, SIPC might run out of money. Unlikely, but worth mentioning. I don't believe that mutual funds have this problem, since they are merely pools of securities. Of course, the securities can drop in value, but other than that, I don't think a mutual fund can go bankrupt. A brokerage can, and if it does, the securities that it holds in the "street name" could be imperiled.