authorize.net vs. CardService International for cc processing

Hi, my client has asked me to get him a merchant account so he can begin to accept credit cards through his site. I see that zencart.com recommends Cardservice international and i also see that there is already a module for authorize.net.

Are there any benefits to using one or the other?

Is one easier to setup and get running?

Is one more reliable?

I will be getting him his own SSL certificate...

Thanks for your help...

Ahren

card services international is the prefered and it uses the linkpoint interface
which is available for zen cart