Credit Card Vs. Online Check

Many online payment systems accepts only credit cards or only checks. The reason is quite simple: there are several differences between the two options.

The most important thing is that getting all you need for accepting credit cards is a lot easier then for online checks. Also by checks there are some returns fees greater then for credit cards.
The advantage of accepting online checks is that you open up your shop to many new customers that do not own a credit card but have a bank account. Some providers offers you the option of using any method.
Ez Payment Services offers support for online payment by credit card or by check

As a customer if you want to use you credit card online there is no problem. All you have to do is find a site that has online shopping and use your credit card just like in an ordinary shop. To accept credit card payments (online, offline, anywhere) you need a credit card Merchant Account.
There are many online providers for merchant accounts so this part is easy to solve.

For online checks there aren't so many providers. Also you need to develop you own software because on the market you will find many shopping cards and other applications for using credit cards online but very few for using online checks.