I think your describtion is pretty good.
To me, i know i'm having great sex while i'm having it, and it doesn't have to last long at all.
I had a boyfriend who always finished very quickly, probably under 5 minutes, but our bodies were so compatible to each other that it felt amazing while it lasted (and probably too amazing for him to last). Of course i would have liked him to continue a bit longer and sometimes i felt unsatisfied after but that doesn't mean it was not good, just i wanted more. Going on too long can also become unsatisfying though, even if it started out great.
If i wanna come vaginally it would have to last longer, but that not necessary for great sex for me (although every time i've come vaginally has been during pretty great sex).
As for taking the time with foreplay beforehand, it can help to get in the mood, but cummin multiple times beforehand may tire me out which could possibly make the sex less great. A hurried quicky could give a just as great rush i think.
Because that is what great sex is to me: a rush, an ecstatic feeling. Sex is kind of an addiction for me because of the feeling it can give when there is enough excitement and bodies connect well.