I think it's a Europe-thingy. I know people in the US regard us as "pussies" when it comes to steriods. We're waaaay to conservative in their eyes. You will rarely see "over 12 week" cycles over here, except for match athletes
2-3 week cycles can be very effective. Your own test won't be shut down as much, cortisone will stay down, your lipid profile will stay ok, your htpa won't be as surpressed, thus less sides also. You will make a full recovery in about 2 weeks, will not lose much gains, if any, dependant on the stuff used.
Most people, educated in steroids, in Europe(or at least in France) use the time-on+PCT=time off. With 4 week cycles, 2 weeks PCT(my favourite), this means 6 weeks rest before you start up your new cycle.
More advanced users wil go time-on=time off. That means you can do 3 small cycles in 12 weeks time.
What can you expect from 2-4 weeks cycles? Small to moderate gains, no to small setback due to the faster recovery.
Obviously for these cycles to work, you need a slightly higher dose, and the fastest acting esthers possible. (di)Prop/ace. Depending on the person, many people feel them after only 2-4 days. If you only feel them after 2 weeks, something is wrong. Either you have fake stuff, or your receptors are burnt out.
Another thing is that smaller cycles aren't the way to go for heavely advanced athletes. IMHO, it's the best choice for martial artist and the likes, as they can't afford a setback, and the short esters will make detection time a lot shorter.