So, they are basically arguing about, how where the syllable stress should lie, isn't it?
Syllable timed - every vowel receives its full value and the time it takes to say a sentence depends on how many syllables there are
Stressed timed - unstressed vowels are severely reduced (or maybe even disappear) and the time it takes to say a sentence depends on the number of _stressed_ syllables there are.
Polish is traditionally syllable timed (with Spanish, Greek, Italian, French) English is stressed timed (along with other Germanic languages)
Sometimes different varieties of the same language differ, European Portuguese is stressed timed and Brazilian more syllable timed, Mexican Spanish is becoming more stress timed (devoicing or eliminating many unstressed syllables).
The harder to define languages have elements of both, maybe because of long and short vowels (Czech, Hungarian) or maybe because vowel reduction occurs wihtout shortening (Russian).