[osCmax v2.5x] Need suggestions to use Paypal Std or IPN

[nirusnailart]

We have installed both Paypal Std and Paypal IPN in 2.5B3 and testing it now. I would like to take suggestions which is best option out of both as first time I am using credit cards and till now only COD in my site.
I want suggestions in scenarios where there is frequent power cut in our country and when the customer confirms checkout and the page goes to Paypal and there is powercut.
1. paypal std doesnt load order in db till it completes the payment. Will the items still be in cart so customer can check out again?
2. In Paypal IPN the order is loaded as Preparing IPN but customer has no option for payment unless they add the same items to cart and confirm again where the same order would be loaded again.

We want to have only one order loaded in db but the payment completed by customer so they get acknowledgement and order showing pending Paypal.

Which is the best options to use considering max powercuts happening.

[michael_s]

IPN.

Once they power is cut to your site, if the customer still has power and completes the paypal order, when your power comes back on, paypal will send the IPN to your store, and the order will automatically be updated to completed status.

If the customer's power goes out, they should have no expectation that the order has been completed or stored anywhere. If they have an account on your site, whatever was in their cart when their power goes out should still be there when they re-login to your site.

[nirusnailart]

IPN.

Once they power is cut to your site, if the customer still has power and completes the paypal order, when your power comes back on, paypal will send the IPN to your store, and the order will automatically be updated to completed status.

If the customer's power goes out, they should have no expectation that the order has been completed or stored anywhere. If they have an account on your site, whatever was in their cart when their power goes out should still be there when they re-login to your site.

Thanks. I simulated the process again. When order process is at Paypal and power goes, order is recorded in admin. I see the products in cart.
1. Switched off the modem and turned on . The browser closed and opened again. Logged in to cart and checked out and proceed to paypal. A new order id is recorded.
2. if Laptop is used and browser still open and items are checked out again, the order id doesnt change.
3. Clicked cancelled and return to email id in paypal site which returns to cart page. Added new products and checkedout again. Now with same order id admin updated the order value.

So Sl. no 1 would remain a issue as most customers would use a desktop and they would reboot when power is recycled. There would be double entry of order. How to overcome this issue.

[nirusnailart]

Simulated the process again
1. When power is recycled at modem and desktop, new order id is created when the cart was checked out again. This is a issue as double order is created at admin side though the customer would not be aware of double entry of order.
2. When used Laptop, the browser is not closed and items checked out from cart, same order id is used for processing the order. New order id is created when browser is closed and logged in to cart and checked out the items.
So Slno1 is a issue as admin would see double entry of orders. Is there a way to resolve it?