I love the effects. It's the best drug I ever used for both size and strength, while making me dry, vascular and hard as nails all at once.
It's great for...
1.) Peaking Strength
2.) Pre-Contest Use: A couple weeks before getting onstage. It's awesome for filling out. People used to use Anadrol for this purpose, but SD is miles better (provides equal or better fullness in most people without the sub-q water).
3.) Plateau Breaking: Short-term; a few weeks (if appetite suppression isn't an issue for you).
4.) Short-Term Appearance Goals: If you have a photoshoot coming up (or similar) with little notice, SD can change your appearance faster than just about anything else. A few weeks is all you need to reap its transient cosmetic benefits.
It's not great for...
1.) A long-term muscle or strength builder: This goes for all methylated AAS due to their negative effects on cardiovascular health. Live toxicity, or toxicity in general, is not really the issue here. When people use the word "toxicity", they usually mean liver toxicity. In most cases, people interpret SD's side effects, such as lethargy, appetite suppression, etc., as a sign as liver toxicity. While liver strain can potentially cause these symptoms, in most cases, the side effects of SD are not due to liver strain. Rather, they are simply the effect of the drug on the brain. Many steroids have caused this effect in people to one degree or another. SD is just worse in this particular side effect department than most other steroids (mg for mg), but it's certainly not the only one. Many, many people have had liver values WAYYYY above of what we typically see with moderate dose SD use, yet completely lacked any of these side effects. This is because the drugs they were using simply weren't know for causing those particular side effects, despite having liver values through the freakin' roof. At this point, we know for a fact that low-moderate dose SD use does not necessarily cause an increase in liver values beyond what is seen with drugs like Dianabol or Anadrol. When compared a mg to mg basis, sure, SD is harder on the liver, but most guys don't use the same doses of SD that they will with other methyls. When used within the effective dosing range (10-20 mg/day), SD is not (generally speaking) any more liver toxic than Anadrol (50-100 mg/day) or Dianabol (30-50 mg/day). Regardless, liver toxicity is not the main reason to avoid the use of methylated drugs. Cardiovascular harm is. This makes all methyls unsuitable for use as a foundational drug.
Now, when it comes to toxicity in other tissues, such as neurons, we simply don't have any research on most of the steroids out there. We do know that trenbolone seems to be particularly toxic in this regard, but this is likely connected to its extremely strong androgenic effect on the brain. SD is a relatively weak androgen, but research is scant (as with many of the drugs bodybuilders use), so we can only speculate.