What's the difference between these two buck topology

One architecture is :

Can&nbsp;anyone&nbsp;list&nbsp;their&nbsp;advantage&nbsp;and&nbsp;disadvantages?<br />

Now&nbsp;I&nbsp;have&nbsp;to&nbsp;select&nbsp;a&nbsp;LED&nbsp;driver&nbsp;of&nbsp;Buck,&nbsp;but&nbsp;I&nbsp;don't&nbsp;know&nbsp;select&nbsp;which&nbsp;one?&nbsp;