Deca doesn't really shut you down harder than other steroids. It's simply a long acting compound. Deca binds to the AR receptor in a different and deeper fashion than does testosterone.....causing a more anabolic response at the intercellular level.
Studies have shown that synthetic esterless testosterone completes it's work and returns to plasma in 1 to 2 hours. Esterless deca, on the other hand, remains bound to the receptor for up to 6 hours. Add in the ester, and you have a long-lasting, effective anabolic drug.
All steroids can cause sexual side effects. No big deal in the age of viagra, cialis, livitor etc. (I swear, powdered viagra will raise the dead, and in a hurry) If such things are a concern, you will want to use some test with all anabolic cycles.