this is just me talking but...
cypro has been *very* effective at blocking t for me, but it wasn't the wonder antiandrogen it should have been
spiro had an initial shock to the system, (which might have been fault for discontinuing cypro too quickly) but seems to be better at helping with secondary effects so far (skin, hair...)
so far the diuretic effect of spiro hasn't been a big whoop issue with me nor limiting of potassium
just my 2 cents