4 caps should suffice for many, in fact there are plenty of users who only do 2 caps and have rather dramatic results.
That said, the 6-8 cap preWO dosing protocol has become extremely popular and does warrant some profound results in terms of newly acquired lean muscle mass. I would only suggest these higher dosed cycles to people who have ran a full cycle at 4 caps first, as some may get joint pain on a dose as high as 8 caps.
Regarding why many prefer to only take it pre workout, it is in order to ensure maximal delivery of the arachidonic acid to skeletal muscle.
Jkerr, thanks for your feedback! We often hear that people are skeptical of the high price tag coming in, but nearly unanimously they report that the results made it worth every penny.