Decca.
Easy on the hair and prostate (both concerns for guys in their 30s - I simply don't want to die of prostate cancer). And no acne, which is nice. No gyno risk. All of the above are greater risks with test. Not ridiculously crazier risks...but I'm old enough to have given up my lust for truly risky "damn-the-torpedos" behavior.
The muscle gains are about the same, mg for mg, for me. Give or take...it's a couple lbs a year, which isn't that big of a deal.
Only thing I miss is the libido, which is still there on decca, but not like it is with test. But being randy all the time isn't worth much if you don't have an outlet...it's frustrating (like being 14 again). Been married too long...wife doesn't care what I'm running...I only get what I get so there's no point wanting it 3x a day when all I'm getting is 1x/week at best.