I think registration for the longer period is good for anybody who register the domain name particularly in the business category. On the other way if you want to change the domain name after two years, it is not possible to change if you have register for five-year period. In that case you need to pay a fee for domain registration. I believe that the shorter term gives you more control over your domain name.
I believe that the two year terms period gives you better control and flexibility so your can renew at anytime to add additional years to your registration term.
