Basically I teste different ways of comparing data and found that isin was the fastest. Then I took it a step further and checked to see which is the fastest to seperate tokens with ... Give me a few and I will show you the test.

Code:
alias SpeedTest {

  ;Test 1
  var %ticks = $ticks
  var %cnt 1
  ; while (%cnt <= %tr) {
  while (%cnt <= 20000) {
    var %ex = $iif(t isin r t s u,yes,no)
    inc %cnt
  }
  msg $active 32: $calc($ticks - %ticks)

  ;Test 2
  var %ticks = $ticks
  var %cnt 1
  while (%cnt <= 20000) {
    var %ex = $iif(t isin r.t.s.u,yes,no)


    inc %cnt
  }
  msg $active 46: $calc($ticks - %ticks)
}

1st try:
32: 1576
46: 1388

2nd try:
32: 1560
46: 1389

3rd:
32: 1575
46: 1404

Using underscore $chr(95) instead of period.
32: 1592
95: 1389

32: 1576
95: 1389

32: 1560
95: 1388

I havent found a faster character. All characters seem to be the same speed except for the space, $chr(32), which is slower to evaluate.