The two misconceptions being promoted here
1. That you can just jump on AAS and magically you will achieve a recomp. Recomping during a blast is very difficult and probably not possible for most people. It takes years of experience to figure out how to train and get your diet just so to allow you to even come close. The reality for most of us is if you want to gain muscle, whether on or off AAS, you need to bulk (eat an excess of 250 to 500 Kcalories or even more each day), which means you will gain fat and muscle during your bulk.
2. That you can gain significant muscle while on aas for short periods. Most super responders to gear may gain 1 to 2 lbs of muscle per week. The rest of us gain that much in a month while on AAS. The rest of our gains are (in the first few weeks) mostly water and glycogen; and fat. In my experience, I gain 10 to 15 lbs of water and glycogen in the first month, and about 1 lb of muscle to possibly 1.5 lbs of muscle per month while I am on.
The biggest mistakes people make while using AAS is to believe that:
i) their initial gains are mostly muscle (instead the initial gains are mostly water and glycogen as just pointed out);
ii) when their initial gains slow their rate of muscle gain has slowed;
Not true, when the gains slow, that is just your body reaching equilibrium with the AAS and initial fluid retention, and is when you will start to see your real rate of gain of both fat and muscle. And when their initial gains slow, many newbies increase the amount of gear to see if they can keep up the initial gains, not realizing that increasing their doses won't help them gain more muscle, and at most will disrupt the equilibrium. The best thing they can do is stay at their original dosage and continue the blast as originally planned.
iii) that you can eat maintenance levels of Kcals and still gain;
This is simply not true for most of us -- you need to eat an excess of Kcals to gain muscle. Most people who are not gaining while blasting are just not eating enough good quality food, period.
iv) that you can make gains with short blasts of 6 to 8 or 10 weeks;
You'll gain maybe 15 lbs of water and glycogen and 1 or 2 lbs of muscle over a 6 to 8 week blast. I ask myself is it worth the stress to my body of using AAS to gain such a small amount? For me the answer is no. For me it's better to blast for 16 to 20 weeks and gain 10 to 15 lbs of muscle than to go through the ups and downs of short cycles, with all their side effects. One thing I have discovered, is that on very long blasts, the side effects diminish quite a bit and my body seems to adapt nicely to the gear I am blasting, even as I continue to gain muscle.