Since credit unions are member-owned, dividends are paid back to the member/shareholders in the form of lower loan rates and higher deposit rates.
However, this is not always the case! If you share the name of the CU you are eligible to join, others would be able to chime in with experience. Also, if you are interested in making the switch, you are probably eligible for other CUs based on your geographic region or membership affiliation. (PTA members are eligible for alliant cu, which has a 4%APY savings... not bad)
One of the benefits people talk about here about CUs is the availability of loans/credit cards with good terms to those with bad credit. If this isn't an issue for you, this may not be a factor.
If you are more interested in using it for checking/savings, look at the terms on the website and compare it to Wachovia. If you are eligible for a credit union with a 4-6% "reward checking" account, that may be an option, otherwise you'll find checking to be similar, with the credit union offering lower fees on the account.
Finally, look at the location of the CU vs the bank. Do you go into a branch to make deposits often? ATM use? If the CU is part of CU Service Centers (most are) you can get full service on your account at ANY participating credit union and use ANY ATM in the CU Svc Ctr network fee free. If you're an online-banking type, check out a demo. The CUs in my area typically have sub-par interfaces compared to Bank of America and USAA, but the good rates may outweigh this.
