I have been looking around at payment gateways and one thing that I discovered is that there are so so many. The most popular seams to be AUTHORIZE.NET.
I am just wondering which payment gateways you use and why?
Paypal is another option that gives customers confidence, but if you make too much money too quickly, they can freeze your account, so your control is very limited. In term of fees, both Ppal and authorize are about the same, with the exception that lots of people have PayPal accounts and find it easier to use PP, especially it has a great buyer protection.
i would prefer to use CCAvenue for payment gateway!!!
If you are based in the UK you can consider Nochex.com.
I am employee of the company, and I use the service myself, so you should do your own research!
Good luck, Peter
Authorize.NET requires a monthly retainer, and for new projects this complicates things. I am considering using PayPal express as oppose to normal PayPal. I will see how things unfold. If your website is not making any money it’s hard to justify paying out unesserily.
I’m preferring to Paypal for eCommerce development because this is high secure but AUTHORIZE.NET is good no problem.
Here is the list, from wikipedia, with payment service providers
Paypal is a best choice as long as you comply with its rules.
Paypal is the best payment gateway according to me because it is quick and easy for buyers to use, especially if they already have a paypal account. It is cheaper and easier to qualify for a PayPal account than a business merchant account.
Selecting a payment gateway and merchant account provider depends on your business type and your company of incorporation.
If you are based in US, Authorize.net is the best possible option as they are the largest payment gateway provider in the world, running highest number of transactions.
Paypal is easy to use but doesn’t protect digital good sellers against chargebacks.
PayPal is so popular that most clients will feel “safe” paying through it, it’s generally accepted as being safe. I personally prefer using Stripe (www.stripe.com), it requires you to do a bit of development but it’s very easy and intuitive to use. It’s a fairly new product so while you can accept payments from anywhere in the world it only currently only supports USD, GBP, CAD and EUR as currencies (all other currencies are converted).
If you can live with the above, I definitely recommend Stripe 
I will suggest you to use PAYPAL because PayPal is most trusted payment gateway and used by so many online businesses for their online transactions.
What kind of service/product you are selling?
For which country?
We use paypal, 2checkout and they are working preety good. It charge around 4.5%.
Paypal or monyebookers. I am always use these two payment gateway.
Most of our clients use Paypal and/or Authorize.net Both are very good. It really depends on what kind of integration you are needing. You need to make sure what ever you pick is PCI compliant.