Two differences:
print has a return value (always 1), echo doesn't. Therefore print can be used as an expression.
echo accepts multiple arguments. So you may write echo $a, $b instead of echo $a . $b.
Concerning the parentheses: They are simply wrong in my eyes. They have no function at all. You could as well write echo (((((((((($a)))))))))); people usually include parentheses from ignorance, thinking that print is a function. Furthermore it increases the chance of misinterpretation. For example print("foo") && print("bar") does not print foobar, because PHP interprets this as print(("foo") && print("bar")). So bar1 would be printed, even though it looks different.
