Money funds vs. high-interest savings account?

Are there any downsides to keeping money in a money fund vs. a high interest savings account? I know that money funds *can* lose value, but I hear it's highly unlikely.

This would be 'emergency fund' money, not an active investment, hence the conservative choice in where to place it.

Some additional info:

I already have a 3% checking account and a brokerage through Schwab, so that's why I hesitate to open yet another account somewhere else for another ~0.75% in a savings (the highest I could find via BankRate.com). It would be just as easy to use the brokerage account to put the cash in a money fund, which is why I asked.

As for liquidity, if it takes a few days that's fine by me for an emergency fund. If my wife or I were to lose our jobs we wouldn't necessarily need the money that instant, it's more for holding us over during lean times should they ever come up.

if it is an "emergency fund" i would but it in a savings account. because i can alway have access to it

yeah, true, a savings account gives you instant access. A money fund... jezus... it'd take 3 business days to put the money in and 3 business days to process and take out.

Opt for maximum liquidity. A high-yield online savings account with ATM access and/or check-writing privileges provides instant access to your funds while earning a decent interest rate (although nothing in this market will be stellar). Check out places like ING DIrect, HSBS and Citi for some online savings products with above-average yields.

Frugal Dad
http://frugaldad.com

In addition to the other responses, money market funds, to which you are referring, and high yield savings accounts are currently yielding about the same interests rates.