For international payments I use PayPal, because that's the speediest, hassle-free, and quality-based paying gateway. Most online retailers have PayPal as a payment option on their commercial platforms. Also PayPal ensures a great deal of flexibility and transparency in every kind of transaction. Moreover, PayPal offers several exciting offers from time to time. So PayPal is better for international payments.
For domestic use I prefer credit/debit cards. All local online retailers have this option of payment. So there's a great deal of flexibility. Also if you have any issue, the issue could be resolved more quickly as you're using it locally and may approach relevant personnel in case of unfair trade practices.