In the recent times a lot of guest checkout options started to appear in all sites where we can buy online. I find this is really convenient because it allows me to buy the items I want without complicated register processes. What about you, do you use this option?
I haven't tried using the guest checkout option because I have a Paypal account from the start, and I always register to the sites that I buy from so that my purchases can be recorded. I think it's better to register to the store that you buy from so that you won't have to go through your email or Paypal account looking for the name or record of the item that you bought.
I have used guest checkout which is fine for a one off purchase or if it's time sensitive and you don't want to fill out too much and then reconfirm which can take ages, but it is worth signing up for various sites to keep a record of transactions. I used Megabus and used the guest check out and then wanted to see my list of journeys and they weren't stored!
It's also good to register because it's then easier for the place to give you good deals (like good pizza-bargains you can have sent to you when youLog In!)
Yes, there are sites that indeed offer us an advantage when we register, but there are many that don't, so we can simply use guest-checkout. The only advantage I see in a full register is the fact that they memorize my data.