The only silver bars that cost more than silver rounds are the most renowned brands like: Johnson Matthey, Engelhard, Pamp Suisse, Credit Suisse. They sell high because they're the most trusted refiners and assayers in the silver market that's why they can command higher premium price and the fact that it's world renowned makes them the easiest to resell if you want to cash it in. Besides from the brands I mentioned there are no difference with the price of bars and rounds, silver brand such as Silvertown, Sunshine and other generic silver bars and rounds have the same price, it would be just a personal preference to choose which shape you want or you can choose both. If you want small increments like 1oz silver choose rounds because they can come in a tube for easy storing, for larger increments (10oz and up) choose stacker bars for easy storing.