yeah i'm trying it at the moment, been doing westside for 2 months now and will give it at least another month or so. The routine is more like a sport specific routine for powerlifting and for the big three lifts squat, bench and deadlift. Because of this many of the golden rules which apply to gaining mass and overall strength are not quite ignored but things like isolation exercises are brought in to address weak points.
The idea of westside is that you train your lifts in two ways: maximum effort and dynamic effort, which is basically going heavy and going fast. Squats and deadlifts are coupled together in training days because they recruit basically same musclegroups, and then benching (or pushing) day is a separate one.
Westside is very, very flexible and there are million variations out there and it can be adapted to other purposes as well than just to work your big 3 lifts.
You cycle your max effort and other exercises very often, usually in my case every other week. On max day you do exactly that, go to your max weights or at least 90-95% of your max.
My current routine:
Maximum effort lower body
squats/deadlifts/good mornings (choose one) work up to 3x3 then 4 singles (exept for GM's)
main assistance movement: front squats/rack pulls/good mornings/bottom position squats etc (choose one) 3x6
bentover rows 3x6
heavy core work
Maximum effort pushing day
bench press/weighed dips/bottom position benches, 3x3 and then up to 4 singles.
Standing barbell shoulder presses 3x6
narrow grip benches 3x6
bicep work (biceps are worked so tri's will grow, the antagonistic muscles always need to be worked for the target muscle to grow)
Dynamic effort lower body
speed squats/speed deads/speed bottom position squats or deep squats 9x2x about 50-60% of your 1 rep max.
power cleans or pull ups 3x8
Dynamic effort upper body
speed benches 9x3 x 50-60% 1RM
shoulder work 3x8
tricep work 3x8
bicep work 3x8
Thats a 7-8 day cycle for me.
Note that i'm a beginner in this, though have been reading a lot about it and have then adapted it to my preferences. Westside trainers often swear by box squats, reverse hypers, using bands and chains to add resistance and so on. I'm not too interested in bands and chains because they are there to emulate the lifting suits and shirts. Box squats i haven't made up my mind yet...