They're pretty much the same, just slightly different syntax as to how to get the condition. Switch requires an extra line of code than if but that's no big deal.
Use which ever one you think makes it easier to read your code. If the condition needs to be made up from multiple tests/operations, then it might be better in an if. switch is best for situations where the condition is just a single value (number, string), or cell array of several such values.
value = (blah + fubar) * snafu
if (blah + fubar) * snafu == 1
elseif (blah + fubar) * snafu == 2 && (someOtherVariable == 3)
My two cents worth, for what it's worth.