Best answer by Mayumi
US Roam AIr @ $1.50 means they will charge you $1.50 per minutes if you make/receive calls in the US.
10ALL includes "Unlimited minutes and texts" and "250 MB of data".
If you don't have a roaming Add-on, you will get charged $1.50 per min, $5 for upto 100 text(outgoing) and $5/20 MB.
If you want to have minutes/text and some data, US Roaming add on would be good idea.
So it all depends on what you need and how much you need.